Merge branch 'development' into fix/instant/signature-denied

* development: (914 commits)
  Unfix compiler version except for top level contracts
  Move OrderValidator to extensions
  Update CHANGELOG
  Remove assembly version of matchOrders
  Add getOrderInfo check before calling fillOrder
  Update comments and hard code function selector constants
  Fix build after rebase
  update comments
  Fix build and add back tests
  Update dependency paths
  Add OrderMatcher tests
  feat: Add OrderMatcher contract that takes spread in multiple assets by calling `matchOrders` followed by `fillOrder`
  Update CHANGELOG
  Use more efficient equality checks
  Add note about input validation
  Use more efficient check for overflow
  Check if amount == 0 before doing division
  Reapply prettier
  New relayers
  feat(sra_client.py): Test deployed pkg via tox
  ...

108 files changed, 4223 insertions, 96 deletions

diff --git a/contracts/.solhint.json b/contracts/.solhint.json
index 076afe9f3..3090d981a 100644
--- a/contracts/.solhint.json
+++ b/contracts/.solhint.json
@@ -5,6 +5,7 @@
         "avoid-tx-origin": "warn",
         "bracket-align": false,
         "code-complexity": false,
+        "compiler-fixed": false,
         "const-name-snakecase": "error",
         "expression-indent": "error",
         "function-max-lines": false,
diff --git a/contracts/examples/package.json b/contracts/examples/package.json
index 77846241e..37b73f98c 100644
--- a/contracts/examples/package.json
+++ b/contracts/examples/package.json
@@ -13,7 +13,8 @@
         "build": "yarn pre_build && tsc -b",
         "build:ci": "yarn build",
         "pre_build": "run-s compile generate_contract_wrappers",
-        "compile": "sol-compiler --contracts-dir contracts",
+        "compile": "sol-compiler",
+        "watch": "sol-compiler -w",
         "clean": "shx rm -rf lib generated-artifacts generated-wrappers",
         "generate_contract_wrappers": "abi-gen --abis  ${npm_package_config_abis} --template ../../node_modules/@0x/abi-gen-templates/contract.handlebars --partials '../../node_modules/@0x/abi-gen-templates/partials/**/*.handlebars' --output generated-wrappers --backend ethers",
         "lint": "tslint --format stylish --project . --exclude ./generated-wrappers/**/* --exclude ./generated-artifacts/**/* --exclude **/lib/**/* && yarn lint-contracts",
diff --git a/contracts/extensions/CHANGELOG.json b/contracts/extensions/CHANGELOG.json
index 19ac770af..083ad33fb 100644
--- a/contracts/extensions/CHANGELOG.json
+++ b/contracts/extensions/CHANGELOG.json
@@ -1,5 +1,22 @@
 [
     {
+        "version": "1.1.0",
+        "changes": [
+            {
+                "note": "Added Balance Threshold Filter",
+                "pr": 1383
+            },
+            {
+                "note": "Add OrderMatcher",
+                "pr": 1117
+            },
+            {
+                "note": "Add OrderValidator",
+                "pr": 1464
+            }
+        ]
+    },
+    {
         "timestamp": 1544741676,
         "version": "1.0.2",
         "changes": [
diff --git a/contracts/extensions/compiler.json b/contracts/extensions/compiler.json
index 69d607b3e..2bb468724 100644
--- a/contracts/extensions/compiler.json
+++ b/contracts/extensions/compiler.json
@@ -18,5 +18,5 @@
             }
         }
     },
-    "contracts": ["DutchAuction", "Forwarder"]
+    "contracts": ["BalanceThresholdFilter", "DutchAuction", "Forwarder", "OrderMatcher", "OrderValidator"]
 }
diff --git a/contracts/extensions/contracts/BalanceThresholdFilter/BalanceThresholdFilter.sol b/contracts/extensions/contracts/BalanceThresholdFilter/BalanceThresholdFilter.sol
new file mode 100644
index 000000000..16cacd461
--- /dev/null
+++ b/contracts/extensions/contracts/BalanceThresholdFilter/BalanceThresholdFilter.sol
@@ -0,0 +1,45 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity 0.4.24;
+
+import "@0x/contracts-interfaces/contracts/protocol/Exchange/IExchange.sol";
+import "./interfaces/IThresholdAsset.sol";
+import "./MixinBalanceThresholdFilterCore.sol";
+
+
+contract BalanceThresholdFilter is
+    MixinBalanceThresholdFilterCore
+{
+
+    /// @dev Constructs BalanceThresholdFilter.
+    /// @param exchange Address of 0x exchange.
+    /// @param thresholdAsset The asset that must be held by makers/takers.
+    /// @param balanceThreshold The minimum balance of `thresholdAsset` that must be held by makers/takers.
+    constructor(
+        address exchange,
+        address thresholdAsset,
+        uint256 balanceThreshold
+    )
+        public
+    {
+        EXCHANGE = IExchange(exchange);
+        THRESHOLD_ASSET = IThresholdAsset(thresholdAsset);
+        BALANCE_THRESHOLD = balanceThreshold;
+    }
+}
diff --git a/contracts/extensions/contracts/BalanceThresholdFilter/MixinBalanceThresholdFilterCore.sol b/contracts/extensions/contracts/BalanceThresholdFilter/MixinBalanceThresholdFilterCore.sol
new file mode 100644
index 000000000..da050bf72
--- /dev/null
+++ b/contracts/extensions/contracts/BalanceThresholdFilter/MixinBalanceThresholdFilterCore.sol
@@ -0,0 +1,135 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+
+import "@0x/contracts-libs/contracts/libs/LibExchangeSelectors.sol";
+import "@0x/contracts-libs/contracts/libs/LibOrder.sol";
+import "./mixins/MBalanceThresholdFilterCore.sol";
+import "./MixinExchangeCalldata.sol";
+
+
+contract MixinBalanceThresholdFilterCore is
+    MBalanceThresholdFilterCore,
+    MixinExchangeCalldata,
+    LibOrder,
+    LibExchangeSelectors
+{
+
+    /// @dev Executes an Exchange transaction iff the maker and taker meet 
+    ///      the hold at least `BALANCE_THRESHOLD` of the asset `THRESHOLD_ASSET` OR 
+    ///      the exchange function is a cancellation.
+    ///      Supported Exchange functions:
+    ///          batchFillOrders
+    ///          batchFillOrdersNoThrow
+    ///          batchFillOrKillOrders
+    ///          fillOrder
+    ///          fillOrderNoThrow
+    ///          fillOrKillOrder
+    ///          marketBuyOrders
+    ///          marketBuyOrdersNoThrow
+    ///          marketSellOrders
+    ///          marketSellOrdersNoThrow
+    ///          matchOrders
+    ///          cancelOrder
+    ///          batchCancelOrders
+    ///          cancelOrdersUpTo
+    ///     Trying to call any other exchange function will throw.
+    /// @param salt Arbitrary number to ensure uniqueness of transaction hash.
+    /// @param signerAddress Address of transaction signer.
+    /// @param signedExchangeTransaction AbiV2 encoded calldata.
+    /// @param signature Proof of signer transaction by signer.
+    function executeTransaction(
+        uint256 salt,
+        address signerAddress,
+        bytes signedExchangeTransaction,
+        bytes signature
+    ) 
+        external
+    {
+        // Get accounts whose balances must be validated
+        address[] memory addressesToValidate = getAddressesToValidate(signerAddress);
+
+        // Validate account balances
+        uint256 balanceThreshold = BALANCE_THRESHOLD;
+        IThresholdAsset thresholdAsset = THRESHOLD_ASSET;
+        for (uint256 i = 0; i < addressesToValidate.length; ++i) {
+            uint256 addressBalance = thresholdAsset.balanceOf(addressesToValidate[i]);
+            require(
+                addressBalance >= balanceThreshold,
+                "AT_LEAST_ONE_ADDRESS_DOES_NOT_MEET_BALANCE_THRESHOLD"
+            );
+        }
+        emit ValidatedAddresses(addressesToValidate);
+        
+        // All addresses are valid. Execute exchange function.
+        EXCHANGE.executeTransaction(
+            salt,
+            signerAddress,
+            signedExchangeTransaction,
+            signature
+        );
+    }
+
+    /// @dev Constructs an array of addresses to be validated.
+    ///      Addresses depend on which Exchange function is to be called
+    ///      (defined by `signedExchangeTransaction` above).
+    /// @param signerAddress Address of transaction signer.
+    /// @return addressesToValidate Array of addresses to validate.
+    function getAddressesToValidate(address signerAddress)
+        internal pure
+        returns (address[] memory addressesToValidate)
+    {
+        bytes4 exchangeFunctionSelector = bytes4(exchangeCalldataload(0));
+        // solhint-disable expression-indent
+        if (
+            exchangeFunctionSelector == BATCH_FILL_ORDERS_SELECTOR              ||
+            exchangeFunctionSelector == BATCH_FILL_ORDERS_NO_THROW_SELECTOR     ||
+            exchangeFunctionSelector == BATCH_FILL_OR_KILL_ORDERS_SELECTOR      ||
+            exchangeFunctionSelector == MARKET_BUY_ORDERS_SELECTOR              ||
+            exchangeFunctionSelector == MARKET_BUY_ORDERS_NO_THROW_SELECTOR     ||
+            exchangeFunctionSelector == MARKET_SELL_ORDERS_SELECTOR             ||
+            exchangeFunctionSelector == MARKET_SELL_ORDERS_NO_THROW_SELECTOR
+        ) {
+            addressesToValidate = loadMakerAddressesFromOrderArray(0);
+            addressesToValidate = addressesToValidate.append(signerAddress);
+        } else if (
+            exchangeFunctionSelector == FILL_ORDER_SELECTOR             ||
+            exchangeFunctionSelector == FILL_ORDER_NO_THROW_SELECTOR    ||
+            exchangeFunctionSelector == FILL_OR_KILL_ORDER_SELECTOR
+        ) {
+            address makerAddress = loadMakerAddressFromOrder(0);
+            addressesToValidate = addressesToValidate.append(makerAddress);
+            addressesToValidate = addressesToValidate.append(signerAddress);
+        } else if (exchangeFunctionSelector == MATCH_ORDERS_SELECTOR) {
+            address leftMakerAddress = loadMakerAddressFromOrder(0);
+            addressesToValidate = addressesToValidate.append(leftMakerAddress);
+            address rightMakerAddress = loadMakerAddressFromOrder(1);
+            addressesToValidate = addressesToValidate.append(rightMakerAddress);
+            addressesToValidate = addressesToValidate.append(signerAddress);
+        } else if (
+            exchangeFunctionSelector != CANCEL_ORDER_SELECTOR           &&
+            exchangeFunctionSelector != BATCH_CANCEL_ORDERS_SELECTOR    &&
+            exchangeFunctionSelector != CANCEL_ORDERS_UP_TO_SELECTOR
+        ) {
+            revert("INVALID_OR_BLOCKED_EXCHANGE_SELECTOR");
+        }
+        // solhint-enable expression-indent
+        return addressesToValidate;
+    }
+}
diff --git a/contracts/extensions/contracts/BalanceThresholdFilter/MixinExchangeCalldata.sol b/contracts/extensions/contracts/BalanceThresholdFilter/MixinExchangeCalldata.sol
new file mode 100644
index 000000000..a15e95a9d
--- /dev/null
+++ b/contracts/extensions/contracts/BalanceThresholdFilter/MixinExchangeCalldata.sol
@@ -0,0 +1,103 @@
+    
+    /*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+
+import "./mixins/MExchangeCalldata.sol";
+import "@0x/contracts-libs/contracts/libs/LibAddressArray.sol";
+
+
+contract MixinExchangeCalldata is 
+    MExchangeCalldata
+{
+
+    using LibAddressArray for address[];
+
+    /// @dev Emulates the `calldataload` opcode on the embedded Exchange calldata,
+    ///      which is accessed through `signedExchangeTransaction`.
+    /// @param offset  Offset into the Exchange calldata.
+    /// @return value  Corresponding 32 byte value stored at `offset`.
+    function exchangeCalldataload(uint256 offset)
+        internal pure
+        returns (bytes32 value)
+    {
+        assembly {
+            // Pointer to exchange transaction
+            // 0x04 for calldata selector
+            // 0x40 to access `signedExchangeTransaction`, which is the third parameter
+            let exchangeTxPtr := calldataload(0x44)
+
+            // Offset into Exchange calldata
+            // We compute this by adding 0x24 to the `exchangeTxPtr` computed above.
+            // 0x04 for calldata selector
+            // 0x20 for length field of `signedExchangeTransaction`
+            let exchangeCalldataOffset := add(exchangeTxPtr, add(0x24, offset))
+            value := calldataload(exchangeCalldataOffset)
+        }
+        return value;
+    }
+
+    /// @dev Convenience function that skips the 4 byte selector when loading
+    ///      from the embedded Exchange calldata.
+    /// @param offset  Offset into the Exchange calldata (minus the 4 byte selector)
+    /// @return value  Corresponding 32 byte value stored at `offset` + 4.
+    function loadExchangeData(uint256 offset)
+        internal pure
+        returns (bytes32 value)
+    {
+        value = exchangeCalldataload(offset + 4);
+        return value;
+    }
+
+    /// @dev Extracts the maker address from an order stored in the Exchange calldata
+    ///      (which is embedded in `signedExchangeTransaction`).
+    /// @param orderParamIndex  Index of the order in the Exchange function's signature.
+    /// @return makerAddress The extracted maker address.
+    function loadMakerAddressFromOrder(uint256 orderParamIndex)
+        internal pure
+        returns (address makerAddress)
+    {
+        uint256 orderOffsetInBytes = orderParamIndex * 32;
+        uint256 orderPtr = uint256(loadExchangeData(orderOffsetInBytes));
+        makerAddress = address(loadExchangeData(orderPtr));
+        return makerAddress;
+    }
+
+    /// @dev Extracts the maker addresses from an array of orders stored in the Exchange calldata
+    ///      (which is embedded in `signedExchangeTransaction`).
+    /// @param orderArrayParamIndex  Index of the order array in the Exchange function's signature
+    /// @return makerAddresses The extracted maker addresses.
+    function loadMakerAddressesFromOrderArray(uint256 orderArrayParamIndex)
+        internal pure
+        returns (address[] makerAddresses)
+    {
+        uint256 orderArrayOffsetInBytes = orderArrayParamIndex * 32;
+        uint256 orderArrayPtr = uint256(loadExchangeData(orderArrayOffsetInBytes));
+        uint256 orderArrayLength = uint256(loadExchangeData(orderArrayPtr));
+        uint256 orderArrayLengthInBytes = orderArrayLength * 32;
+        uint256 orderArrayElementPtr = orderArrayPtr + 32;
+        uint256 orderArrayElementEndPtr = orderArrayElementPtr + orderArrayLengthInBytes;
+        for (uint orderPtrOffset = orderArrayElementPtr; orderPtrOffset < orderArrayElementEndPtr; orderPtrOffset += 32) {
+            uint256 orderPtr = uint256(loadExchangeData(orderPtrOffset));
+            address makerAddress = address(loadExchangeData(orderPtr + orderArrayElementPtr));
+            makerAddresses = makerAddresses.append(makerAddress);
+        }
+        return makerAddresses;
+    }
+}
diff --git a/contracts/extensions/contracts/BalanceThresholdFilter/interfaces/IBalanceThresholdFilterCore.sol b/contracts/extensions/contracts/BalanceThresholdFilter/interfaces/IBalanceThresholdFilterCore.sol
new file mode 100644
index 000000000..4a1bf1fb2
--- /dev/null
+++ b/contracts/extensions/contracts/BalanceThresholdFilter/interfaces/IBalanceThresholdFilterCore.sol
@@ -0,0 +1,55 @@
+
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+
+
+contract IBalanceThresholdFilterCore {
+    
+    /// @dev Executes an Exchange transaction iff the maker and taker meet 
+    ///      the hold at least `BALANCE_THRESHOLD` of the asset `THRESHOLD_ASSET` OR 
+    ///      the exchange function is a cancellation.
+    ///      Supported Exchange functions:
+    ///         - batchFillOrders
+    ///         - batchFillOrdersNoThrow
+    ///         - batchFillOrKillOrders
+    ///         - fillOrder
+    ///         - fillOrderNoThrow
+    ///         - fillOrKillOrder
+    ///         - marketBuyOrders
+    ///         - marketBuyOrdersNoThrow
+    ///         - marketSellOrders
+    ///         - marketSellOrdersNoThrow
+    ///         - matchOrders
+    ///         - cancelOrder
+    ///         - batchCancelOrders
+    ///         - cancelOrdersUpTo
+    ///     Trying to call any other exchange function will throw.
+    /// @param salt Arbitrary number to ensure uniqueness of transaction hash.
+    /// @param signerAddress Address of transaction signer.
+    /// @param signedExchangeTransaction AbiV2 encoded calldata.
+    /// @param signature Proof of signer transaction by signer.
+    function executeTransaction(
+        uint256 salt,
+        address signerAddress,
+        bytes signedExchangeTransaction,
+        bytes signature
+    ) 
+        external;
+}
diff --git a/contracts/extensions/contracts/BalanceThresholdFilter/interfaces/IThresholdAsset.sol b/contracts/extensions/contracts/BalanceThresholdFilter/interfaces/IThresholdAsset.sol
new file mode 100644
index 000000000..f78f9c2de
--- /dev/null
+++ b/contracts/extensions/contracts/BalanceThresholdFilter/interfaces/IThresholdAsset.sol
@@ -0,0 +1,31 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+
+
+contract IThresholdAsset {
+
+    /// @param _owner The address from which the balance will be retrieved
+    /// @return Balance of owner
+    function balanceOf(address _owner)
+        external
+        view
+        returns (uint256);
+
+}
diff --git a/contracts/extensions/contracts/BalanceThresholdFilter/mixins/MBalanceThresholdFilterCore.sol b/contracts/extensions/contracts/BalanceThresholdFilter/mixins/MBalanceThresholdFilterCore.sol
new file mode 100644
index 000000000..074686e8d
--- /dev/null
+++ b/contracts/extensions/contracts/BalanceThresholdFilter/mixins/MBalanceThresholdFilterCore.sol
@@ -0,0 +1,54 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+
+import "@0x/contracts-interfaces/contracts/protocol/Exchange/IExchange.sol";
+import "../interfaces/IThresholdAsset.sol";
+import "../interfaces/IBalanceThresholdFilterCore.sol";
+
+
+contract MBalanceThresholdFilterCore is
+    IBalanceThresholdFilterCore
+{
+
+    // Points to 0x exchange contract
+    // solhint-disable var-name-mixedcase
+    IExchange internal EXCHANGE;
+
+    // The asset that must be held by makers/takers
+    IThresholdAsset internal THRESHOLD_ASSET;
+
+    // The minimum balance of `THRESHOLD_ASSET` that must be held by makers/takers
+    uint256 internal BALANCE_THRESHOLD;
+    // solhint-enable var-name-mixedcase
+
+    // Addresses that hold at least `BALANCE_THRESHOLD` of `THRESHOLD_ASSET`
+    event ValidatedAddresses (
+        address[] addresses
+    );
+
+    /// @dev Constructs an array of addresses to be validated.
+    ///      Addresses depend on which Exchange function is to be called
+    ///      (defined by `signedExchangeTransaction` above).
+    /// @param signerAddress Address of transaction signer.
+    /// @return addressesToValidate Array of addresses to validate.
+    function getAddressesToValidate(address signerAddress)
+        internal pure
+        returns (address[] memory addressesToValidate);
+}
diff --git a/contracts/extensions/contracts/BalanceThresholdFilter/mixins/MExchangeCalldata.sol b/contracts/extensions/contracts/BalanceThresholdFilter/mixins/MExchangeCalldata.sol
new file mode 100644
index 000000000..40536d820
--- /dev/null
+++ b/contracts/extensions/contracts/BalanceThresholdFilter/mixins/MExchangeCalldata.sol
@@ -0,0 +1,56 @@
+    
+    /*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+
+
+contract MExchangeCalldata {
+
+    /// @dev Emulates the `calldataload` opcode on the embedded Exchange calldata,
+    ///      which is accessed through `signedExchangeTransaction`.
+    /// @param offset  Offset into the Exchange calldata.
+    /// @return value  Corresponding 32 byte value stored at `offset`.
+    function exchangeCalldataload(uint256 offset)
+        internal pure
+        returns (bytes32 value);
+
+    /// @dev Convenience function that skips the 4 byte selector when loading
+    ///      from the embedded Exchange calldata.
+    /// @param offset  Offset into the Exchange calldata (minus the 4 byte selector)
+    /// @return value  Corresponding 32 byte value stored at `offset` + 4.
+    function loadExchangeData(uint256 offset)
+        internal pure
+        returns (bytes32 value);
+
+    /// @dev Extracts the maker address from an order stored in the Exchange calldata
+    ///      (which is embedded in `signedExchangeTransaction`).
+    /// @param orderParamIndex  Index of the order in the Exchange function's signature.
+    /// @return makerAddress The extracted maker address.
+    function loadMakerAddressFromOrder(uint256 orderParamIndex)
+        internal pure
+        returns (address makerAddress);
+
+    /// @dev Extracts the maker addresses from an array of orders stored in the Exchange calldata
+    ///      (which is embedded in `signedExchangeTransaction`).
+    /// @param orderArrayParamIndex  Index of the order array in the Exchange function's signature
+    /// @return makerAddresses The extracted maker addresses.
+    function loadMakerAddressesFromOrderArray(uint256 orderArrayParamIndex)
+        internal pure
+        returns (address[] makerAddresses);
+}
diff --git a/contracts/extensions/contracts/Forwarder/MixinAssets.sol b/contracts/extensions/contracts/Forwarder/MixinAssets.sol
index 3ebf75161..116cdf267 100644
--- a/contracts/extensions/contracts/Forwarder/MixinAssets.sol
+++ b/contracts/extensions/contracts/Forwarder/MixinAssets.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity 0.4.24;
+pragma solidity ^0.4.24;
 
 import "@0x/contracts-utils/contracts/utils/LibBytes/LibBytes.sol";
 import "@0x/contracts-utils/contracts/utils/Ownable/Ownable.sol";
diff --git a/contracts/extensions/contracts/Forwarder/MixinExchangeWrapper.sol b/contracts/extensions/contracts/Forwarder/MixinExchangeWrapper.sol
index 210eb14c2..cab26741d 100644
--- a/contracts/extensions/contracts/Forwarder/MixinExchangeWrapper.sol
+++ b/contracts/extensions/contracts/Forwarder/MixinExchangeWrapper.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity 0.4.24;
+pragma solidity ^0.4.24;
 pragma experimental ABIEncoderV2;
 
 import "./libs/LibConstants.sol";
diff --git a/contracts/extensions/contracts/Forwarder/MixinForwarderCore.sol b/contracts/extensions/contracts/Forwarder/MixinForwarderCore.sol
index bab78d79b..11c0147a5 100644
--- a/contracts/extensions/contracts/Forwarder/MixinForwarderCore.sol
+++ b/contracts/extensions/contracts/Forwarder/MixinForwarderCore.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity 0.4.24;
+pragma solidity ^0.4.24;
 pragma experimental ABIEncoderV2;
 
 import "./libs/LibConstants.sol";
diff --git a/contracts/extensions/contracts/Forwarder/MixinWeth.sol b/contracts/extensions/contracts/Forwarder/MixinWeth.sol
index 2a281f3ae..25a35f47b 100644
--- a/contracts/extensions/contracts/Forwarder/MixinWeth.sol
+++ b/contracts/extensions/contracts/Forwarder/MixinWeth.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity 0.4.24;
+pragma solidity ^0.4.24;
 
 import "@0x/contracts-libs/contracts/libs/LibMath.sol";
 import "./libs/LibConstants.sol";
diff --git a/contracts/extensions/contracts/Forwarder/interfaces/IAssets.sol b/contracts/extensions/contracts/Forwarder/interfaces/IAssets.sol
index 1e034c003..cebfd3706 100644
--- a/contracts/extensions/contracts/Forwarder/interfaces/IAssets.sol
+++ b/contracts/extensions/contracts/Forwarder/interfaces/IAssets.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity 0.4.24;
+pragma solidity ^0.4.24;
 
 
 contract IAssets {
diff --git a/contracts/extensions/contracts/Forwarder/interfaces/IForwarder.sol b/contracts/extensions/contracts/Forwarder/interfaces/IForwarder.sol
index f5a26e2ba..6ce8a1d31 100644
--- a/contracts/extensions/contracts/Forwarder/interfaces/IForwarder.sol
+++ b/contracts/extensions/contracts/Forwarder/interfaces/IForwarder.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity 0.4.24;
+pragma solidity ^0.4.24;
 pragma experimental ABIEncoderV2;
 
 import "./IForwarderCore.sol";
diff --git a/contracts/extensions/contracts/Forwarder/interfaces/IForwarderCore.sol b/contracts/extensions/contracts/Forwarder/interfaces/IForwarderCore.sol
index eede20bb8..7f62722e7 100644
--- a/contracts/extensions/contracts/Forwarder/interfaces/IForwarderCore.sol
+++ b/contracts/extensions/contracts/Forwarder/interfaces/IForwarderCore.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity 0.4.24;
+pragma solidity ^0.4.24;
 pragma experimental ABIEncoderV2;
 
 import "@0x/contracts-libs/contracts/libs/LibOrder.sol";
diff --git a/contracts/extensions/contracts/Forwarder/libs/LibConstants.sol b/contracts/extensions/contracts/Forwarder/libs/LibConstants.sol
index 4a81abf76..0d2f6e36d 100644
--- a/contracts/extensions/contracts/Forwarder/libs/LibConstants.sol
+++ b/contracts/extensions/contracts/Forwarder/libs/LibConstants.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity 0.4.24;
+pragma solidity ^0.4.24;
 
 import "@0x/contracts-utils/contracts/utils/LibBytes/LibBytes.sol";
 import "@0x/contracts-interfaces/contracts/protocol/Exchange/IExchange.sol";
diff --git a/contracts/extensions/contracts/Forwarder/libs/LibForwarderErrors.sol b/contracts/extensions/contracts/Forwarder/libs/LibForwarderErrors.sol
index fb3ade1db..7a95b78a0 100644
--- a/contracts/extensions/contracts/Forwarder/libs/LibForwarderErrors.sol
+++ b/contracts/extensions/contracts/Forwarder/libs/LibForwarderErrors.sol
@@ -17,7 +17,7 @@
 */
 
 // solhint-disable
-pragma solidity 0.4.24;
+pragma solidity ^0.4.24;
 
 
 /// This contract is intended to serve as a reference, but is not actually used for efficiency reasons.
diff --git a/contracts/extensions/contracts/Forwarder/mixins/MAssets.sol b/contracts/extensions/contracts/Forwarder/mixins/MAssets.sol
index 9e7f80d97..1757b37fb 100644
--- a/contracts/extensions/contracts/Forwarder/mixins/MAssets.sol
+++ b/contracts/extensions/contracts/Forwarder/mixins/MAssets.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity 0.4.24;
+pragma solidity ^0.4.24;
 
 import "../interfaces/IAssets.sol";
 
diff --git a/contracts/extensions/contracts/Forwarder/mixins/MExchangeWrapper.sol b/contracts/extensions/contracts/Forwarder/mixins/MExchangeWrapper.sol
index d9e71786a..143f888b1 100644
--- a/contracts/extensions/contracts/Forwarder/mixins/MExchangeWrapper.sol
+++ b/contracts/extensions/contracts/Forwarder/mixins/MExchangeWrapper.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity 0.4.24;
+pragma solidity ^0.4.24;
 pragma experimental ABIEncoderV2;
 
 import "@0x/contracts-libs/contracts/libs/LibOrder.sol";
diff --git a/contracts/extensions/contracts/Forwarder/mixins/MWeth.sol b/contracts/extensions/contracts/Forwarder/mixins/MWeth.sol
index 88e77be4e..15d66942f 100644
--- a/contracts/extensions/contracts/Forwarder/mixins/MWeth.sol
+++ b/contracts/extensions/contracts/Forwarder/mixins/MWeth.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity 0.4.24;
+pragma solidity ^0.4.24;
 
 
 contract MWeth {
diff --git a/contracts/extensions/contracts/OrderMatcher/MixinAssets.sol b/contracts/extensions/contracts/OrderMatcher/MixinAssets.sol
new file mode 100644
index 000000000..f0f91cfc0
--- /dev/null
+++ b/contracts/extensions/contracts/OrderMatcher/MixinAssets.sol
@@ -0,0 +1,195 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+
+import "@0x/contracts-utils/contracts/utils/LibBytes/LibBytes.sol";
+import "@0x/contracts-utils/contracts/utils/Ownable/Ownable.sol";
+import "@0x/contracts-tokens/contracts/tokens/ERC20Token/IERC20Token.sol";
+import "@0x/contracts-tokens/contracts/tokens/ERC721Token/IERC721Token.sol";
+import "./mixins/MAssets.sol";
+import "./libs/LibConstants.sol";
+
+
+contract MixinAssets is
+    MAssets,
+    Ownable,
+    LibConstants
+{
+    using LibBytes for bytes;
+
+    /// @dev Withdraws assets from this contract. The contract requires a ZRX balance in order to 
+    ///      function optimally, and this function allows the ZRX to be withdrawn by owner. It may also be
+    ///      used to withdraw assets that were accidentally sent to this contract.
+    /// @param assetData Byte array encoded for the respective asset proxy.
+    /// @param amount Amount of asset to withdraw.
+    function withdrawAsset(
+        bytes assetData,
+        uint256 amount
+    )
+        external
+        onlyOwner
+    {
+        transferAssetToSender(assetData, amount);
+    }
+
+    /// @dev Approves or disapproves an AssetProxy to spend asset.
+    /// @param assetData Byte array encoded for the respective asset proxy.
+    /// @param amount Amount of asset to approve for respective proxy.
+    function approveAssetProxy(
+        bytes assetData,
+        uint256 amount
+    )
+        external
+        onlyOwner
+    {
+        bytes4 proxyId = assetData.readBytes4(0);
+
+        if (proxyId == ERC20_DATA_ID) {
+            approveERC20Token(assetData, amount);
+        } else if (proxyId == ERC721_DATA_ID) {
+            approveERC721Token(assetData, amount);
+        } else {
+            revert("UNSUPPORTED_ASSET_PROXY");
+        }
+    }
+
+    /// @dev Transfers given amount of asset to sender.
+    /// @param assetData Byte array encoded for the respective asset proxy.
+    /// @param amount Amount of asset to transfer to sender.
+    function transferAssetToSender(
+        bytes memory assetData,
+        uint256 amount
+    )
+        internal
+    {
+        bytes4 proxyId = assetData.readBytes4(0);
+
+        if (proxyId == ERC20_DATA_ID) {
+            transferERC20Token(assetData, amount);
+        } else if (proxyId == ERC721_DATA_ID) {
+            transferERC721Token(assetData, amount);
+        } else {
+            revert("UNSUPPORTED_ASSET_PROXY");
+        }
+    }
+
+    /// @dev Decodes ERC20 assetData and transfers given amount to sender.
+    /// @param assetData Byte array encoded for the respective asset proxy.
+    /// @param amount Amount of asset to transfer to sender.
+    function transferERC20Token(
+        bytes memory assetData,
+        uint256 amount
+    )
+        internal
+    {
+        // 4 byte id + 12 0 bytes before ABI encoded token address.
+        address token = assetData.readAddress(16);
+
+        // Transfer tokens.
+        // We do a raw call so we can check the success separate
+        // from the return data.
+        bool success = token.call(abi.encodeWithSelector(
+            ERC20_TRANSFER_SELECTOR,
+            msg.sender,
+            amount
+        ));
+        require(
+            success,
+            "TRANSFER_FAILED"
+        );
+        
+        // Check return data.
+        // If there is no return data, we assume the token incorrectly
+        // does not return a bool. In this case we expect it to revert
+        // on failure, which was handled above.
+        // If the token does return data, we require that it is a single
+        // value that evaluates to true.
+        assembly {
+            if returndatasize {
+                success := 0
+                if eq(returndatasize, 32) {
+                    // First 64 bytes of memory are reserved scratch space
+                    returndatacopy(0, 0, 32)
+                    success := mload(0)
+                }
+            }
+        }
+        require(
+            success,
+            "TRANSFER_FAILED"
+        );
+    }
+
+    /// @dev Decodes ERC721 assetData and transfers given amount to sender.
+    /// @param assetData Byte array encoded for the respective asset proxy.
+    /// @param amount Amount of asset to transfer to sender.
+    function transferERC721Token(
+        bytes memory assetData,
+        uint256 amount
+    )
+        internal
+    {
+        require(
+            amount == 1,
+            "INVALID_AMOUNT"
+        );
+        // Decode asset data.
+        // 4 byte id + 12 0 bytes before ABI encoded token address.
+        address token = assetData.readAddress(16);
+        // 4 byte id + 32 byte ABI encoded token address before token id.
+        uint256 tokenId = assetData.readUint256(36);
+
+        // Perform transfer.
+        IERC721Token(token).transferFrom(
+            address(this),
+            msg.sender,
+            tokenId
+        );
+    }
+
+    /// @dev Sets approval for ERC20 AssetProxy.
+    /// @param assetData Byte array encoded for the respective asset proxy.
+    /// @param amount Amount of asset to approve for respective proxy.
+    function approveERC20Token(
+        bytes memory assetData,
+        uint256 amount
+    )
+        internal
+    {
+        address token = assetData.readAddress(16);
+        require(
+            IERC20Token(token).approve(ERC20_PROXY_ADDRESS, amount),
+            "APPROVAL_FAILED"
+        );
+    }
+
+    /// @dev Sets approval for ERC721 AssetProxy.
+    /// @param assetData Byte array encoded for the respective asset proxy.
+    /// @param amount Amount of asset to approve for respective proxy.
+    function approveERC721Token(
+        bytes memory assetData,
+        uint256 amount
+    )
+        internal
+    {
+        address token = assetData.readAddress(16);
+        bool approval = amount >= 1;
+        IERC721Token(token).setApprovalForAll(ERC721_PROXY_ADDRESS, approval);
+    }
+}
diff --git a/contracts/extensions/contracts/OrderMatcher/MixinMatchOrders.sol b/contracts/extensions/contracts/OrderMatcher/MixinMatchOrders.sol
new file mode 100644
index 000000000..1787deb59
--- /dev/null
+++ b/contracts/extensions/contracts/OrderMatcher/MixinMatchOrders.sol
@@ -0,0 +1,86 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+pragma experimental ABIEncoderV2;
+
+import "./libs/LibConstants.sol";
+import "@0x/contracts-libs/contracts/libs/LibOrder.sol";
+import "@0x/contracts-libs/contracts/libs/LibFillResults.sol";
+import "@0x/contracts-utils/contracts/utils/Ownable/Ownable.sol";
+
+
+contract MixinMatchOrders is
+    Ownable,
+    LibConstants
+{
+    /// @dev Match two complementary orders that have a profitable spread.
+    ///      Each order is filled at their respective price point. However, the calculations are
+    ///      carried out as though the orders are both being filled at the right order's price point.
+    ///      The profit made by the left order is then used to fill the right order as much as possible.
+    ///      This results in a spread being taken in terms of both assets. The spread is held within this contract.
+    /// @param leftOrder First order to match.
+    /// @param rightOrder Second order to match.
+    /// @param leftSignature Proof that order was created by the left maker.
+    /// @param rightSignature Proof that order was created by the right maker.
+    function matchOrders(
+        LibOrder.Order memory leftOrder,
+        LibOrder.Order memory rightOrder,
+        bytes memory leftSignature,
+        bytes memory rightSignature
+    )
+        public
+        onlyOwner
+    {
+        // Match orders, maximally filling `leftOrder`
+        LibFillResults.MatchedFillResults memory matchedFillResults = EXCHANGE.matchOrders(
+            leftOrder,
+            rightOrder,
+            leftSignature,
+            rightSignature
+        );
+
+        uint256 leftMakerAssetSpreadAmount = matchedFillResults.leftMakerAssetSpreadAmount;
+        uint256 rightOrderTakerAssetAmount = rightOrder.takerAssetAmount;
+
+        // Do not attempt to call `fillOrder` if no spread was taken or `rightOrder` has been completely filled
+        if (leftMakerAssetSpreadAmount == 0 || matchedFillResults.right.takerAssetFilledAmount == rightOrderTakerAssetAmount) {
+            return;
+        }
+
+        // The `assetData` fields of the `rightOrder` could have been null for the `matchOrders` call. We reassign them before calling `fillOrder`.
+        rightOrder.makerAssetData = leftOrder.takerAssetData;
+        rightOrder.takerAssetData = leftOrder.makerAssetData;
+
+        // Query `rightOrder` info to check if it has been completely filled
+        // We need to make this check in case the `rightOrder` was partially filled before the `matchOrders` call
+        LibOrder.OrderInfo memory orderInfo = EXCHANGE.getOrderInfo(rightOrder);
+
+        // Do not attempt to call `fillOrder` if order has been completely filled
+        if (orderInfo.orderTakerAssetFilledAmount == rightOrderTakerAssetAmount) {
+            return;
+        }
+
+        // We do not need to pass in a signature since it was already validated in the `matchOrders` call
+        EXCHANGE.fillOrder(
+            rightOrder,
+            leftMakerAssetSpreadAmount,
+            ""
+        );
+    }
+}
diff --git a/contracts/extensions/contracts/OrderMatcher/OrderMatcher.sol b/contracts/extensions/contracts/OrderMatcher/OrderMatcher.sol
new file mode 100644
index 000000000..4879b7bca
--- /dev/null
+++ b/contracts/extensions/contracts/OrderMatcher/OrderMatcher.sol
@@ -0,0 +1,38 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity 0.4.24;
+pragma experimental ABIEncoderV2;
+
+import "@0x/contracts-utils/contracts/utils/Ownable/Ownable.sol";
+import "./libs/LibConstants.sol";
+import "./MixinMatchOrders.sol";
+import "./MixinAssets.sol";
+
+
+// solhint-disable no-empty-blocks
+contract OrderMatcher is
+    MixinMatchOrders,
+    MixinAssets
+{
+    constructor (address _exchange)
+        public
+        LibConstants(_exchange)
+        Ownable()
+    {}
+}
diff --git a/contracts/extensions/contracts/OrderMatcher/interfaces/IAssets.sol b/contracts/extensions/contracts/OrderMatcher/interfaces/IAssets.sol
new file mode 100644
index 000000000..9fcc0023a
--- /dev/null
+++ b/contracts/extensions/contracts/OrderMatcher/interfaces/IAssets.sol
@@ -0,0 +1,43 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+
+
+contract IAssets {
+
+    /// @dev Withdraws assets from this contract. The contract requires a ZRX balance in order to 
+    ///      function optimally, and this function allows the ZRX to be withdrawn by owner. It may also be
+    ///      used to withdraw assets that were accidentally sent to this contract.
+    /// @param assetData Byte array encoded for the respective asset proxy.
+    /// @param amount Amount of asset to withdraw.
+    function withdrawAsset(
+        bytes assetData,
+        uint256 amount
+    )
+        external;
+
+    /// @dev Approves or disapproves an AssetProxy to spend asset.
+    /// @param assetData Byte array encoded for the respective asset proxy.
+    /// @param amount Amount of asset to approve for respective proxy.
+    function approveAssetProxy(
+        bytes assetData,
+        uint256 amount
+    )
+        external;
+}
diff --git a/contracts/extensions/contracts/OrderMatcher/interfaces/IMatchOrders.sol b/contracts/extensions/contracts/OrderMatcher/interfaces/IMatchOrders.sol
new file mode 100644
index 000000000..1443c73b9
--- /dev/null
+++ b/contracts/extensions/contracts/OrderMatcher/interfaces/IMatchOrders.sol
@@ -0,0 +1,43 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+pragma experimental ABIEncoderV2;
+
+import "@0x/contracts-libs/contracts/libs/LibOrder.sol";
+
+
+contract IMatchOrders {
+
+    /// @dev Match two complementary orders that have a profitable spread.
+    ///      Each order is filled at their respective price point. However, the calculations are
+    ///      carried out as though the orders are both being filled at the right order's price point.
+    ///      The profit made by the left order is then used to fill the right order as much as possible.
+    ///      This results in a spread being taken in terms of both assets. The spread is held within this contract.
+    /// @param leftOrder First order to match.
+    /// @param rightOrder Second order to match.
+    /// @param leftSignature Proof that order was created by the left maker.
+    /// @param rightSignature Proof that order was created by the right maker.
+    function matchOrders(
+        LibOrder.Order memory leftOrder,
+        LibOrder.Order memory rightOrder,
+        bytes memory leftSignature,
+        bytes memory rightSignature
+    )
+        public;
+}
diff --git a/contracts/extensions/contracts/OrderMatcher/interfaces/IOrderMatcher.sol b/contracts/extensions/contracts/OrderMatcher/interfaces/IOrderMatcher.sol
new file mode 100644
index 000000000..75f26dca6
--- /dev/null
+++ b/contracts/extensions/contracts/OrderMatcher/interfaces/IOrderMatcher.sol
@@ -0,0 +1,31 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+
+import "@0x/contract-utils/contracts/utils/Ownable/IOwnable.sol";
+import "./IMatchOrders.sol";
+import "./IAssets.sol";
+
+
+// solhint-disable no-empty-blocks
+contract IOrderMatcher is
+    IOwnable,
+    IMatchOrders,
+    IAssets
+{}
diff --git a/contracts/extensions/contracts/OrderMatcher/libs/LibConstants.sol b/contracts/extensions/contracts/OrderMatcher/libs/LibConstants.sol
new file mode 100644
index 000000000..c1a86a9c7
--- /dev/null
+++ b/contracts/extensions/contracts/OrderMatcher/libs/LibConstants.sol
@@ -0,0 +1,56 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+
+import "@0x/contracts-interfaces/contracts/protocol/Exchange/IExchange.sol";
+
+
+contract LibConstants {
+
+    // bytes4(keccak256("transfer(address,uint256)"))
+    bytes4 constant internal ERC20_TRANSFER_SELECTOR = 0xa9059cbb;
+    // bytes4(keccak256("ERC20Token(address)"))
+    bytes4 constant internal ERC20_DATA_ID = 0xf47261b0;
+    // bytes4(keccak256("ERC721Token(address,uint256)"))
+    bytes4 constant internal ERC721_DATA_ID = 0x02571792;
+ 
+     // solhint-disable var-name-mixedcase
+    IExchange internal EXCHANGE;
+    address internal ERC20_PROXY_ADDRESS;
+    address internal ERC721_PROXY_ADDRESS;
+    // solhint-enable var-name-mixedcase
+
+    constructor (address _exchange)
+        public
+    {
+        EXCHANGE = IExchange(_exchange);
+
+        ERC20_PROXY_ADDRESS = EXCHANGE.getAssetProxy(ERC20_DATA_ID);
+        require(
+            ERC20_PROXY_ADDRESS != address(0),
+            "UNREGISTERED_ASSET_PROXY"
+        );
+
+        ERC721_PROXY_ADDRESS = EXCHANGE.getAssetProxy(ERC721_DATA_ID);
+        require(
+            ERC721_PROXY_ADDRESS != address(0),
+            "UNREGISTERED_ASSET_PROXY"
+        );
+    }
+}
diff --git a/contracts/extensions/contracts/OrderMatcher/mixins/MAssets.sol b/contracts/extensions/contracts/OrderMatcher/mixins/MAssets.sol
new file mode 100644
index 000000000..6ea7a3290
--- /dev/null
+++ b/contracts/extensions/contracts/OrderMatcher/mixins/MAssets.sol
@@ -0,0 +1,71 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+
+import "../interfaces/IAssets.sol";
+
+
+contract MAssets is
+    IAssets
+{
+    /// @dev Transfers given amount of asset to sender.
+    /// @param assetData Byte array encoded for the respective asset proxy.
+    /// @param amount Amount of asset to transfer to sender.
+    function transferAssetToSender(
+        bytes memory assetData,
+        uint256 amount
+    )
+        internal;
+
+    /// @dev Decodes ERC20 assetData and transfers given amount to sender.
+    /// @param assetData Byte array encoded for the respective asset proxy.
+    /// @param amount Amount of asset to transfer to sender.
+    function transferERC20Token(
+        bytes memory assetData,
+        uint256 amount
+    )
+        internal;
+
+    /// @dev Decodes ERC721 assetData and transfers given amount to sender.
+    /// @param assetData Byte array encoded for the respective asset proxy.
+    /// @param amount Amount of asset to transfer to sender.
+    function transferERC721Token(
+        bytes memory assetData,
+        uint256 amount
+    )
+        internal;
+
+    /// @dev Sets approval for ERC20 AssetProxy.
+    /// @param assetData Byte array encoded for the respective asset proxy.
+    /// @param amount Amount of asset to approve for respective proxy.
+    function approveERC20Token(
+        bytes memory assetData,
+        uint256 amount
+    )
+        internal;
+
+    /// @dev Sets approval for ERC721 AssetProxy.
+    /// @param assetData Byte array encoded for the respective asset proxy.
+    /// @param amount Amount of asset to approve for respective proxy.
+    function approveERC721Token(
+        bytes memory assetData,
+        uint256 amount
+    )
+        internal;
+}
diff --git a/contracts/protocol/contracts/protocol/OrderValidator/OrderValidator.sol b/contracts/extensions/contracts/OrderValidator/OrderValidator.sol
index 33dd1326c..33dd1326c 100644
--- a/contracts/protocol/contracts/protocol/OrderValidator/OrderValidator.sol
+++ b/contracts/extensions/contracts/OrderValidator/OrderValidator.sol
diff --git a/contracts/extensions/package.json b/contracts/extensions/package.json
index 938e1138c..069b5d2d5 100644
--- a/contracts/extensions/package.json
+++ b/contracts/extensions/package.json
@@ -19,7 +19,8 @@
         "test:profiler": "SOLIDITY_PROFILER=true run-s build run_mocha profiler:report:html",
         "test:trace": "SOLIDITY_REVERT_TRACE=true run-s build run_mocha",
         "run_mocha": "mocha --require source-map-support/register --require make-promises-safe 'lib/test/**/*.js' --timeout 100000 --bail --exit",
-        "compile": "sol-compiler --contracts-dir contracts",
+        "compile": "sol-compiler",
+        "watch": "sol-compiler -w",
         "clean": "shx rm -rf lib generated-artifacts generated-wrappers",
         "generate_contract_wrappers": "abi-gen --abis  ${npm_package_config_abis} --template ../../node_modules/@0x/abi-gen-templates/contract.handlebars --partials '../../node_modules/@0x/abi-gen-templates/partials/**/*.handlebars' --output generated-wrappers --backend ethers",
         "lint": "tslint --format stylish --project . --exclude ./generated-wrappers/**/* --exclude ./generated-artifacts/**/* --exclude **/lib/**/* && yarn lint-contracts",
@@ -31,7 +32,7 @@
         "lint-contracts": "solhint -c ../.solhint.json contracts/**/**/**/**/*.sol"
     },
     "config": {
-        "abis": "generated-artifacts/@(DutchAuction|Forwarder).json"
+        "abis": "generated-artifacts/@(BalanceThresholdFilter|DutchAuction|Forwarder|OrderMatcher|OrderValidator).json"
     },
     "repository": {
         "type": "git",
diff --git a/contracts/extensions/src/artifacts/index.ts b/contracts/extensions/src/artifacts/index.ts
index 7588178f0..329d0f3f3 100644
--- a/contracts/extensions/src/artifacts/index.ts
+++ b/contracts/extensions/src/artifacts/index.ts
@@ -1,9 +1,15 @@
 import { ContractArtifact } from 'ethereum-types';
 
+import * as BalanceThresholdFilter from '../../generated-artifacts/BalanceThresholdFilter.json';
 import * as DutchAuction from '../../generated-artifacts/DutchAuction.json';
 import * as Forwarder from '../../generated-artifacts/Forwarder.json';
+import * as OrderMatcher from '../../generated-artifacts/OrderMatcher.json';
+import * as OrderValidator from '../../generated-artifacts/OrderValidator.json';
 
 export const artifacts = {
+    BalanceThresholdFilter: BalanceThresholdFilter as ContractArtifact,
     DutchAuction: DutchAuction as ContractArtifact,
     Forwarder: Forwarder as ContractArtifact,
+    OrderMatcher: OrderMatcher as ContractArtifact,
+    OrderValidator: OrderValidator as ContractArtifact,
 };
diff --git a/contracts/extensions/src/wrappers/index.ts b/contracts/extensions/src/wrappers/index.ts
index 90880e37f..65aec3ccd 100644
--- a/contracts/extensions/src/wrappers/index.ts
+++ b/contracts/extensions/src/wrappers/index.ts
@@ -1,2 +1,5 @@
+export * from '../../generated-wrappers/balance_threshold_filter';
 export * from '../../generated-wrappers/dutch_auction';
 export * from '../../generated-wrappers/forwarder';
+export * from '../../generated-wrappers/order_matcher';
+export * from '../../generated-wrappers/order_validator';
diff --git a/contracts/extensions/test/extensions/balance_threshold_filter.ts b/contracts/extensions/test/extensions/balance_threshold_filter.ts
new file mode 100644
index 000000000..07199d60b
--- /dev/null
+++ b/contracts/extensions/test/extensions/balance_threshold_filter.ts
@@ -0,0 +1,1644 @@
+import { BlockchainLifecycle } from '@0x/dev-utils';
+import { assetDataUtils } from '@0x/order-utils';
+import { Order, RevertReason, SignedOrder } from '@0x/types';
+import { BigNumber } from '@0x/utils';
+import { Web3Wrapper } from '@0x/web3-wrapper';
+import * as chai from 'chai';
+import { TransactionReceiptWithDecodedLogs } from 'ethereum-types';
+import * as _ from 'lodash';
+
+import {
+    artifacts as protocolArtifacts,
+    ERC20Wrapper,
+    ERC721Wrapper,
+    ExchangeContract,
+    ExchangeWrapper,
+} from '@0x/contracts-protocol';
+import {
+    chaiSetup,
+    constants,
+    ContractName,
+    ERC20BalancesByOwner,
+    expectTransactionFailedAsync,
+    OrderFactory,
+    OrderStatus,
+    provider,
+    TransactionFactory,
+    txDefaults,
+    web3Wrapper,
+} from '@0x/contracts-test-utils';
+import { DummyERC20TokenContract } from '@0x/contracts-tokens';
+
+import { BalanceThresholdFilterContract } from '../../generated-wrappers/balance_threshold_filter';
+import { artifacts } from '../../src/artifacts';
+import { BalanceThresholdWrapper } from '../utils/balance_threshold_wrapper';
+
+chaiSetup.configure();
+const expect = chai.expect;
+const blockchainLifecycle = new BlockchainLifecycle(web3Wrapper);
+const DECIMALS_DEFAULT = 18;
+
+interface ValidatedAddressesLog {
+    args: { addresses: string[] };
+}
+
+describe(ContractName.BalanceThresholdFilter, () => {
+    const takerAssetAmount = Web3Wrapper.toBaseUnitAmount(new BigNumber(500), DECIMALS_DEFAULT);
+    const makerAssetAmount = Web3Wrapper.toBaseUnitAmount(new BigNumber(1000), DECIMALS_DEFAULT);
+    const takerAssetFillAmount = Web3Wrapper.toBaseUnitAmount(new BigNumber(250), DECIMALS_DEFAULT);
+
+    let validMakerAddress: string;
+    let validMakerAddress2: string;
+    let owner: string;
+    let validTakerAddress: string;
+    let feeRecipientAddress: string;
+    let invalidAddress: string;
+    let defaultMakerAssetAddress: string;
+    let defaultTakerAssetAddress: string;
+    let zrxAssetData: string;
+    let zrxToken: DummyERC20TokenContract;
+    let exchangeInstance: ExchangeContract;
+    let exchangeWrapper: ExchangeWrapper;
+
+    let orderFactory: OrderFactory;
+    let orderFactory2: OrderFactory;
+    let invalidOrderFactory: OrderFactory;
+    let erc20Wrapper: ERC20Wrapper;
+    let erc20Balances: ERC20BalancesByOwner;
+    let erc20TakerBalanceThresholdWrapper: BalanceThresholdWrapper;
+    let erc721TakerBalanceThresholdWrapper: BalanceThresholdWrapper;
+    let erc721MakerBalanceThresholdWrapper: BalanceThresholdWrapper;
+    let erc721NonValidBalanceThresholdWrapper: BalanceThresholdWrapper;
+
+    let defaultOrderParams: Partial<Order>;
+    let validSignedOrder: SignedOrder;
+    let validSignedOrder2: SignedOrder;
+
+    let erc721BalanceThresholdFilterInstance: BalanceThresholdFilterContract;
+    let erc20BalanceThresholdFilterInstance: BalanceThresholdFilterContract;
+
+    const assertValidatedAddressesLog = async (
+        txReceipt: TransactionReceiptWithDecodedLogs,
+        expectedValidatedAddresses: string[],
+    ) => {
+        expect(txReceipt.logs.length).to.be.gte(1);
+        const validatedAddressesLog = (txReceipt.logs[0] as any) as ValidatedAddressesLog;
+        const validatedAddresses = validatedAddressesLog.args.addresses;
+        // @HACK-hysz: Nested addresses are not translated to lower-case but this will change once
+        //             the new ABI Encoder/Decoder is used by the contract templates.
+        const validatedAddressesNormalized: string[] = [];
+        _.each(validatedAddresses, address => {
+            const normalizedAddress = _.toLower(address);
+            validatedAddressesNormalized.push(normalizedAddress);
+        });
+        expect(validatedAddressesNormalized).to.be.deep.equal(expectedValidatedAddresses);
+    };
+
+    before(async () => {
+        // Create accounts
+        await blockchainLifecycle.startAsync();
+        const accounts = await web3Wrapper.getAvailableAddressesAsync();
+        const usedAddresses = ([
+            owner,
+            validMakerAddress,
+            validMakerAddress2,
+            validTakerAddress,
+            feeRecipientAddress,
+            invalidAddress,
+        ] = accounts);
+        const takerPrivateKey = constants.TESTRPC_PRIVATE_KEYS[accounts.indexOf(validTakerAddress)];
+        const makerPrivateKey = constants.TESTRPC_PRIVATE_KEYS[accounts.indexOf(validMakerAddress)];
+        const secondMakerPrivateKey = constants.TESTRPC_PRIVATE_KEYS[accounts.indexOf(validMakerAddress2)];
+        const invalidAddressPrivateKey = constants.TESTRPC_PRIVATE_KEYS[accounts.indexOf(invalidAddress)];
+        // Create wrappers
+        erc20Wrapper = new ERC20Wrapper(provider, usedAddresses, owner);
+        const validAddresses = _.cloneDeepWith(usedAddresses);
+        _.remove(validAddresses, (address: string) => {
+            return address === invalidAddress;
+        });
+        const erc721Wrapper = new ERC721Wrapper(provider, validAddresses, owner);
+        // Deploy ERC20 tokens
+        const numDummyErc20ToDeploy = 4;
+        let erc20TokenA: DummyERC20TokenContract;
+        let erc20TokenB: DummyERC20TokenContract;
+        let erc20BalanceThresholdAsset: DummyERC20TokenContract;
+        [erc20TokenA, erc20TokenB, zrxToken, erc20BalanceThresholdAsset] = await erc20Wrapper.deployDummyTokensAsync(
+            numDummyErc20ToDeploy,
+            constants.DUMMY_TOKEN_DECIMALS,
+        );
+        defaultMakerAssetAddress = erc20TokenA.address;
+        defaultTakerAssetAddress = erc20TokenB.address;
+        zrxAssetData = assetDataUtils.encodeERC20AssetData(zrxToken.address);
+        // Create proxies
+        const erc20Proxy = await erc20Wrapper.deployProxyAsync();
+        await erc20Wrapper.setBalancesAndAllowancesAsync();
+        // Deploy Exchange contract
+        exchangeInstance = await ExchangeContract.deployFrom0xArtifactAsync(
+            protocolArtifacts.Exchange,
+            provider,
+            txDefaults,
+            zrxAssetData,
+        );
+        exchangeWrapper = new ExchangeWrapper(exchangeInstance, provider);
+        // Register proxies
+        await exchangeWrapper.registerAssetProxyAsync(erc20Proxy.address, owner);
+        await erc20Proxy.addAuthorizedAddress.sendTransactionAsync(exchangeInstance.address, {
+            from: owner,
+        });
+        // Deploy Balance Threshold Filters
+        // One uses an ERC721 token as its balance threshold asset; the other uses an ERC20
+        const erc721alanceThreshold = new BigNumber(1);
+        await erc721Wrapper.deployProxyAsync();
+        const [erc721BalanceThresholdAsset] = await erc721Wrapper.deployDummyTokensAsync();
+        await erc721Wrapper.setBalancesAndAllowancesAsync();
+        erc721BalanceThresholdFilterInstance = await BalanceThresholdFilterContract.deployFrom0xArtifactAsync(
+            artifacts.BalanceThresholdFilter,
+            provider,
+            txDefaults,
+            exchangeInstance.address,
+            erc721BalanceThresholdAsset.address,
+            erc721alanceThreshold,
+        );
+        const erc20BalanceThreshold = Web3Wrapper.toBaseUnitAmount(new BigNumber(1), 10);
+        erc20BalanceThresholdFilterInstance = await BalanceThresholdFilterContract.deployFrom0xArtifactAsync(
+            artifacts.BalanceThresholdFilter,
+            provider,
+            txDefaults,
+            exchangeInstance.address,
+            erc20BalanceThresholdAsset.address,
+            erc20BalanceThreshold,
+        );
+        // Default order parameters
+        defaultOrderParams = {
+            exchangeAddress: exchangeInstance.address,
+            feeRecipientAddress,
+            makerAssetData: assetDataUtils.encodeERC20AssetData(defaultMakerAssetAddress),
+            takerAssetData: assetDataUtils.encodeERC20AssetData(defaultTakerAssetAddress),
+            makerAssetAmount,
+            takerAssetAmount,
+            makerFee: Web3Wrapper.toBaseUnitAmount(new BigNumber(100), DECIMALS_DEFAULT),
+            takerFee: Web3Wrapper.toBaseUnitAmount(new BigNumber(150), DECIMALS_DEFAULT),
+            senderAddress: erc721BalanceThresholdFilterInstance.address,
+        };
+        // Create two order factories with valid makers (who meet the threshold balance), and
+        // one factory for an invalid address (that does not meet the threshold balance)
+        // Valid order factory #1
+        const defaultOrderParams1 = {
+            makerAddress: validMakerAddress,
+            ...defaultOrderParams,
+        };
+        orderFactory = new OrderFactory(makerPrivateKey, defaultOrderParams1);
+        // Valid order factory #2
+        const defaultOrderParams2 = {
+            makerAddress: validMakerAddress2,
+            ...defaultOrderParams,
+        };
+        orderFactory2 = new OrderFactory(secondMakerPrivateKey, defaultOrderParams2);
+        // Invalid order factory
+        const defaultNonValidOrderParams = {
+            makerAddress: invalidAddress,
+            ...defaultOrderParams,
+        };
+        invalidOrderFactory = new OrderFactory(invalidAddressPrivateKey, defaultNonValidOrderParams);
+        // Create Balance Thresold Wrappers
+        erc20TakerBalanceThresholdWrapper = new BalanceThresholdWrapper(
+            erc20BalanceThresholdFilterInstance,
+            exchangeInstance,
+            new TransactionFactory(takerPrivateKey, exchangeInstance.address),
+            provider,
+        );
+        erc721TakerBalanceThresholdWrapper = new BalanceThresholdWrapper(
+            erc721BalanceThresholdFilterInstance,
+            exchangeInstance,
+            new TransactionFactory(takerPrivateKey, exchangeInstance.address),
+            provider,
+        );
+        erc721MakerBalanceThresholdWrapper = new BalanceThresholdWrapper(
+            erc721BalanceThresholdFilterInstance,
+            exchangeInstance,
+            new TransactionFactory(makerPrivateKey, exchangeInstance.address),
+            provider,
+        );
+        erc721NonValidBalanceThresholdWrapper = new BalanceThresholdWrapper(
+            erc721BalanceThresholdFilterInstance,
+            exchangeInstance,
+            new TransactionFactory(invalidAddressPrivateKey, exchangeInstance.address),
+            provider,
+        );
+    });
+    beforeEach(async () => {
+        await blockchainLifecycle.startAsync();
+    });
+    afterEach(async () => {
+        await blockchainLifecycle.revertAsync();
+    });
+
+    describe('General Sanity Checks', () => {
+        beforeEach(async () => {
+            erc20Balances = await erc20Wrapper.getBalancesAsync();
+            validSignedOrder = await orderFactory.newSignedOrderAsync();
+            validSignedOrder2 = await orderFactory2.newSignedOrderAsync();
+        });
+        it('should transfer the correct amounts and validate both maker/taker when both maker and taker exceed the balance threshold of an ERC20 token', async () => {
+            const validSignedOrderERC20Sender = await orderFactory.newSignedOrderAsync({
+                ...defaultOrderParams,
+                makerAddress: validMakerAddress,
+                senderAddress: erc20TakerBalanceThresholdWrapper.getBalanceThresholdAddress(),
+            });
+            // Execute a valid fill
+            const txReceipt = await erc20TakerBalanceThresholdWrapper.fillOrderAsync(
+                validSignedOrderERC20Sender,
+                validTakerAddress,
+                { takerAssetFillAmount },
+            );
+            // Assert validated addresses
+            const expectedValidatedAddresseses = [validSignedOrder.makerAddress, validTakerAddress];
+            await assertValidatedAddressesLog(txReceipt, expectedValidatedAddresseses);
+            // Check balances
+            const newBalances = await erc20Wrapper.getBalancesAsync();
+            const makerAssetFillAmount = takerAssetFillAmount
+                .times(validSignedOrder.makerAssetAmount)
+                .dividedToIntegerBy(validSignedOrder.takerAssetAmount);
+            const makerFeePaid = validSignedOrder.makerFee
+                .times(makerAssetFillAmount)
+                .dividedToIntegerBy(validSignedOrder.makerAssetAmount);
+            const takerFeePaid = validSignedOrder.takerFee
+                .times(makerAssetFillAmount)
+                .dividedToIntegerBy(validSignedOrder.makerAssetAmount);
+            expect(newBalances[validMakerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[validMakerAddress][defaultMakerAssetAddress].minus(makerAssetFillAmount),
+            );
+            expect(newBalances[validMakerAddress][defaultTakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[validMakerAddress][defaultTakerAssetAddress].add(takerAssetFillAmount),
+            );
+            expect(newBalances[validMakerAddress][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[validMakerAddress][zrxToken.address].minus(makerFeePaid),
+            );
+            expect(newBalances[validTakerAddress][defaultTakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[validTakerAddress][defaultTakerAssetAddress].minus(takerAssetFillAmount),
+            );
+            expect(newBalances[validTakerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[validTakerAddress][defaultMakerAssetAddress].add(makerAssetFillAmount),
+            );
+            expect(newBalances[validTakerAddress][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[validTakerAddress][zrxToken.address].minus(takerFeePaid),
+            );
+            expect(newBalances[feeRecipientAddress][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[feeRecipientAddress][zrxToken.address].add(makerFeePaid.add(takerFeePaid)),
+            );
+        });
+        it('should revert if the Exchange transaction function is not supported', async () => {
+            // Create signed order without the fillOrder function selector
+            const salt = new BigNumber(0);
+            const badSelectorHex = '0x00000000';
+            const signatureHex = '0x';
+            // Call valid forwarder
+            return expectTransactionFailedAsync(
+                erc721BalanceThresholdFilterInstance.executeTransaction.sendTransactionAsync(
+                    salt,
+                    validTakerAddress,
+                    badSelectorHex,
+                    signatureHex,
+                ),
+                RevertReason.InvalidOrBlockedExchangeSelector,
+            );
+        });
+        it('should revert if senderAddress is not set to the valid forwarding contract', async () => {
+            // Create signed order with incorrect senderAddress
+            const notBalanceThresholdFilterAddress = zrxToken.address;
+            const signedOrderWithBadSenderAddress = await orderFactory.newSignedOrderAsync({
+                senderAddress: notBalanceThresholdFilterAddress,
+            });
+            // Call valid forwarder
+            return expectTransactionFailedAsync(
+                erc721TakerBalanceThresholdWrapper.fillOrderAsync(signedOrderWithBadSenderAddress, validTakerAddress, {
+                    takerAssetFillAmount,
+                }),
+                RevertReason.FailedExecution,
+            );
+        });
+    });
+
+    describe('batchFillOrders', () => {
+        beforeEach(async () => {
+            erc20Balances = await erc20Wrapper.getBalancesAsync();
+            validSignedOrder = await orderFactory.newSignedOrderAsync();
+            validSignedOrder2 = await orderFactory2.newSignedOrderAsync();
+        });
+        it('should transfer the correct amounts and validate both makers/taker when both maker and taker meet the balance threshold', async () => {
+            // Execute a valid fill
+            const orders = [validSignedOrder, validSignedOrder2];
+            const takerAssetFillAmounts = [takerAssetFillAmount, takerAssetFillAmount];
+            const txReceipt = await erc721TakerBalanceThresholdWrapper.batchFillOrdersAsync(orders, validTakerAddress, {
+                takerAssetFillAmounts,
+            });
+            // Assert validated addresses
+            const expectedValidatedAddresseses = [
+                validSignedOrder.makerAddress,
+                validSignedOrder2.makerAddress,
+                validTakerAddress,
+            ];
+            await assertValidatedAddressesLog(txReceipt, expectedValidatedAddresseses);
+            // Check balances
+            const newBalances = await erc20Wrapper.getBalancesAsync();
+            const cumulativeTakerAssetFillAmount = takerAssetFillAmount.times(2);
+            const makerAssetFillAmount = takerAssetFillAmount
+                .times(validSignedOrder.makerAssetAmount)
+                .dividedToIntegerBy(validSignedOrder.takerAssetAmount);
+            const makerFeePaid = validSignedOrder.makerFee
+                .times(makerAssetFillAmount)
+                .dividedToIntegerBy(validSignedOrder.makerAssetAmount);
+            const takerFeePaid = validSignedOrder.takerFee
+                .times(makerAssetFillAmount)
+                .dividedToIntegerBy(validSignedOrder.makerAssetAmount)
+                .times(2);
+            // Maker #1
+            expect(newBalances[validMakerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[validMakerAddress][defaultMakerAssetAddress].minus(makerAssetFillAmount),
+            );
+            expect(newBalances[validMakerAddress][defaultTakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[validMakerAddress][defaultTakerAssetAddress].add(takerAssetFillAmount),
+            );
+            expect(newBalances[validMakerAddress][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[validMakerAddress][zrxToken.address].minus(makerFeePaid),
+            );
+            // Maker #2
+            expect(newBalances[validMakerAddress2][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[validMakerAddress2][defaultMakerAssetAddress].minus(makerAssetFillAmount),
+            );
+            expect(newBalances[validMakerAddress2][defaultTakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[validMakerAddress2][defaultTakerAssetAddress].add(takerAssetFillAmount),
+            );
+            expect(newBalances[validMakerAddress2][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[validMakerAddress2][zrxToken.address].minus(makerFeePaid),
+            );
+            // Taker
+            expect(newBalances[validTakerAddress][defaultTakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[validTakerAddress][defaultTakerAssetAddress].minus(cumulativeTakerAssetFillAmount),
+            );
+
+            expect(newBalances[validTakerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[validTakerAddress][defaultMakerAssetAddress].add(makerAssetFillAmount.times(2)),
+            );
+            expect(newBalances[validTakerAddress][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[validTakerAddress][zrxToken.address].minus(takerFeePaid),
+            );
+            // Fee recipient
+            expect(newBalances[feeRecipientAddress][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[feeRecipientAddress][zrxToken.address].add(makerFeePaid.times(2).add(takerFeePaid)),
+            );
+        });
+        it('should revert if one maker does not meet the balance threshold', async () => {
+            // Create order set with one non-valid maker address
+            const takerAssetFillAmounts = [takerAssetFillAmount, takerAssetFillAmount];
+            const signedOrderWithBadMakerAddress = await orderFactory.newSignedOrderAsync({
+                makerAddress: invalidAddress,
+            });
+            const orders = [validSignedOrder, signedOrderWithBadMakerAddress];
+            // Execute transaction
+            return expectTransactionFailedAsync(
+                erc721TakerBalanceThresholdWrapper.batchFillOrdersAsync(orders, validTakerAddress, {
+                    takerAssetFillAmounts,
+                }),
+                RevertReason.AtLeastOneAddressDoesNotMeetBalanceThreshold,
+            );
+        });
+        it('should revert if taker does not meet the balance threshold', async () => {
+            const orders = [validSignedOrder, validSignedOrder2];
+            const takerAssetFillAmounts = [takerAssetFillAmount, takerAssetFillAmount];
+            return expectTransactionFailedAsync(
+                erc721NonValidBalanceThresholdWrapper.batchFillOrdersAsync(orders, invalidAddress, {
+                    takerAssetFillAmounts,
+                }),
+                RevertReason.AtLeastOneAddressDoesNotMeetBalanceThreshold,
+            );
+        });
+    });
+
+    describe('batchFillOrdersNoThrow', () => {
+        beforeEach(async () => {
+            erc20Balances = await erc20Wrapper.getBalancesAsync();
+            validSignedOrder = await orderFactory.newSignedOrderAsync();
+            validSignedOrder2 = await orderFactory2.newSignedOrderAsync();
+        });
+        it('should transfer the correct amounts and validate both makers/taker when both maker and taker meet the balance threshold', async () => {
+            // Execute a valid fill
+            const orders = [validSignedOrder, validSignedOrder2];
+            const takerAssetFillAmounts = [takerAssetFillAmount, takerAssetFillAmount];
+            const txReceipt = await erc721TakerBalanceThresholdWrapper.batchFillOrdersNoThrowAsync(
+                orders,
+                validTakerAddress,
+                {
+                    takerAssetFillAmounts,
+                    // HACK(albrow): We need to hardcode the gas estimate here because
+                    // the Geth gas estimator doesn't work with the way we use
+                    // delegatecall and swallow errors.
+                    gas: 600000,
+                },
+            );
+            // Assert validated addresses
+            const expectedValidatedAddresseses = [
+                validSignedOrder.makerAddress,
+                validSignedOrder2.makerAddress,
+                validTakerAddress,
+            ];
+            await assertValidatedAddressesLog(txReceipt, expectedValidatedAddresseses);
+            // Check balances
+            const newBalances = await erc20Wrapper.getBalancesAsync();
+            const cumulativeTakerAssetFillAmount = takerAssetFillAmount.times(2);
+            const makerAssetFillAmount = takerAssetFillAmount
+                .times(validSignedOrder.makerAssetAmount)
+                .dividedToIntegerBy(validSignedOrder.takerAssetAmount);
+            const makerFeePaid = validSignedOrder.makerFee
+                .times(makerAssetFillAmount)
+                .dividedToIntegerBy(validSignedOrder.makerAssetAmount);
+            const takerFeePaid = validSignedOrder.takerFee
+                .times(makerAssetFillAmount)
+                .dividedToIntegerBy(validSignedOrder.makerAssetAmount)
+                .times(2);
+            // Maker #1
+            expect(newBalances[validMakerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[validMakerAddress][defaultMakerAssetAddress].minus(makerAssetFillAmount),
+            );
+            expect(newBalances[validMakerAddress][defaultTakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[validMakerAddress][defaultTakerAssetAddress].add(takerAssetFillAmount),
+            );
+            expect(newBalances[validMakerAddress][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[validMakerAddress][zrxToken.address].minus(makerFeePaid),
+            );
+            // Maker #2
+            expect(newBalances[validMakerAddress2][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[validMakerAddress2][defaultMakerAssetAddress].minus(makerAssetFillAmount),
+            );
+            expect(newBalances[validMakerAddress2][defaultTakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[validMakerAddress2][defaultTakerAssetAddress].add(takerAssetFillAmount),
+            );
+            expect(newBalances[validMakerAddress2][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[validMakerAddress2][zrxToken.address].minus(makerFeePaid),
+            );
+            // Taker
+            expect(newBalances[validTakerAddress][defaultTakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[validTakerAddress][defaultTakerAssetAddress].minus(cumulativeTakerAssetFillAmount),
+            );
+
+            expect(newBalances[validTakerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[validTakerAddress][defaultMakerAssetAddress].add(makerAssetFillAmount.times(2)),
+            );
+            expect(newBalances[validTakerAddress][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[validTakerAddress][zrxToken.address].minus(takerFeePaid),
+            );
+            // Fee recipient
+            expect(newBalances[feeRecipientAddress][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[feeRecipientAddress][zrxToken.address].add(makerFeePaid.times(2).add(takerFeePaid)),
+            );
+        });
+        it('should revert if one maker does not meet the balance threshold', async () => {
+            // Create order set with one non-valid maker address
+            const takerAssetFillAmounts = [takerAssetFillAmount, takerAssetFillAmount];
+            const signedOrderWithBadMakerAddress = await orderFactory.newSignedOrderAsync({
+                makerAddress: invalidAddress,
+            });
+            const orders = [validSignedOrder, signedOrderWithBadMakerAddress];
+            // Execute transaction
+            return expectTransactionFailedAsync(
+                erc721TakerBalanceThresholdWrapper.batchFillOrdersNoThrowAsync(orders, validTakerAddress, {
+                    takerAssetFillAmounts,
+                }),
+                RevertReason.AtLeastOneAddressDoesNotMeetBalanceThreshold,
+            );
+        });
+        it('should revert if taker does not meet the balance threshold', async () => {
+            const orders = [validSignedOrder, validSignedOrder2];
+            const takerAssetFillAmounts = [takerAssetFillAmount, takerAssetFillAmount];
+            return expectTransactionFailedAsync(
+                erc721NonValidBalanceThresholdWrapper.batchFillOrdersNoThrowAsync(orders, invalidAddress, {
+                    takerAssetFillAmounts,
+                }),
+                RevertReason.AtLeastOneAddressDoesNotMeetBalanceThreshold,
+            );
+        });
+    });
+
+    describe('batchFillOrKillOrders', () => {
+        beforeEach(async () => {
+            erc20Balances = await erc20Wrapper.getBalancesAsync();
+            validSignedOrder = await orderFactory.newSignedOrderAsync();
+            validSignedOrder2 = await orderFactory2.newSignedOrderAsync();
+        });
+        it('should transfer the correct amounts and validate both makers/taker when both makers and taker meet the balance threshold', async () => {
+            // Execute a valid fill
+            const orders = [validSignedOrder, validSignedOrder2];
+            const takerAssetFillAmounts = [takerAssetFillAmount, takerAssetFillAmount];
+            const txReceipt = await erc721TakerBalanceThresholdWrapper.batchFillOrKillOrdersAsync(
+                orders,
+                validTakerAddress,
+                { takerAssetFillAmounts },
+            );
+            // Assert validated addresses
+            const expectedValidatedAddresseses = [
+                validSignedOrder.makerAddress,
+                validSignedOrder2.makerAddress,
+                validTakerAddress,
+            ];
+            await assertValidatedAddressesLog(txReceipt, expectedValidatedAddresseses);
+            // Check balances
+            const newBalances = await erc20Wrapper.getBalancesAsync();
+            const cumulativeTakerAssetFillAmount = takerAssetFillAmount.times(2);
+            const makerAssetFillAmount = takerAssetFillAmount
+                .times(validSignedOrder.makerAssetAmount)
+                .dividedToIntegerBy(validSignedOrder.takerAssetAmount);
+            const makerFeePaid = validSignedOrder.makerFee
+                .times(makerAssetFillAmount)
+                .dividedToIntegerBy(validSignedOrder.makerAssetAmount);
+            const takerFeePaid = validSignedOrder.takerFee
+                .times(makerAssetFillAmount)
+                .dividedToIntegerBy(validSignedOrder.makerAssetAmount)
+                .times(2);
+            // Maker #1
+            expect(newBalances[validMakerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[validMakerAddress][defaultMakerAssetAddress].minus(makerAssetFillAmount),
+            );
+            expect(newBalances[validMakerAddress][defaultTakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[validMakerAddress][defaultTakerAssetAddress].add(takerAssetFillAmount),
+            );
+            expect(newBalances[validMakerAddress][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[validMakerAddress][zrxToken.address].minus(makerFeePaid),
+            );
+            // Maker #2
+            expect(newBalances[validMakerAddress2][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[validMakerAddress2][defaultMakerAssetAddress].minus(makerAssetFillAmount),
+            );
+            expect(newBalances[validMakerAddress2][defaultTakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[validMakerAddress2][defaultTakerAssetAddress].add(takerAssetFillAmount),
+            );
+            expect(newBalances[validMakerAddress2][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[validMakerAddress2][zrxToken.address].minus(makerFeePaid),
+            );
+            // Taker
+            expect(newBalances[validTakerAddress][defaultTakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[validTakerAddress][defaultTakerAssetAddress].minus(cumulativeTakerAssetFillAmount),
+            );
+
+            expect(newBalances[validTakerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[validTakerAddress][defaultMakerAssetAddress].add(makerAssetFillAmount.times(2)),
+            );
+            expect(newBalances[validTakerAddress][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[validTakerAddress][zrxToken.address].minus(takerFeePaid),
+            );
+            // Fee recipient
+            expect(newBalances[feeRecipientAddress][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[feeRecipientAddress][zrxToken.address].add(makerFeePaid.times(2).add(takerFeePaid)),
+            );
+        });
+        it('should revert if one maker does not meet the balance threshold', async () => {
+            // Create order set with one non-valid maker address
+            const takerAssetFillAmounts = [takerAssetFillAmount, takerAssetFillAmount];
+            const signedOrderWithBadMakerAddress = await orderFactory.newSignedOrderAsync({
+                makerAddress: invalidAddress,
+            });
+            const orders = [validSignedOrder, signedOrderWithBadMakerAddress];
+            // Execute transaction
+            return expectTransactionFailedAsync(
+                erc721TakerBalanceThresholdWrapper.batchFillOrKillOrdersAsync(orders, validTakerAddress, {
+                    takerAssetFillAmounts,
+                }),
+                RevertReason.AtLeastOneAddressDoesNotMeetBalanceThreshold,
+            );
+        });
+        it('should revert if taker does not meet the balance threshold', async () => {
+            const orders = [validSignedOrder, validSignedOrder2];
+            const takerAssetFillAmounts = [takerAssetFillAmount, takerAssetFillAmount];
+            return expectTransactionFailedAsync(
+                erc721NonValidBalanceThresholdWrapper.batchFillOrKillOrdersAsync(orders, invalidAddress, {
+                    takerAssetFillAmounts,
+                }),
+                RevertReason.AtLeastOneAddressDoesNotMeetBalanceThreshold,
+            );
+        });
+        it('should revert if one takerAssetFillAmount is not fully filled', async () => {
+            const tooBigTakerAssetFillAmount = validSignedOrder.takerAssetAmount.times(2);
+            const orders = [validSignedOrder, validSignedOrder2];
+            const takerAssetFillAmounts = [takerAssetFillAmount, tooBigTakerAssetFillAmount];
+            return expectTransactionFailedAsync(
+                erc721TakerBalanceThresholdWrapper.batchFillOrKillOrdersAsync(orders, validTakerAddress, {
+                    takerAssetFillAmounts,
+                }),
+                RevertReason.FailedExecution,
+            );
+        });
+    });
+
+    describe('fillOrder', () => {
+        beforeEach(async () => {
+            erc20Balances = await erc20Wrapper.getBalancesAsync();
+            validSignedOrder = await orderFactory.newSignedOrderAsync();
+        });
+        it('should transfer the correct amounts and validate both maker/taker when both maker and taker meet the balance threshold', async () => {
+            // Execute a valid fill
+            const txReceipt = await erc721TakerBalanceThresholdWrapper.fillOrderAsync(
+                validSignedOrder,
+                validTakerAddress,
+                { takerAssetFillAmount },
+            );
+            // Assert validated addresses
+            const expectedValidatedAddresseses = [validSignedOrder.makerAddress, validTakerAddress];
+            await assertValidatedAddressesLog(txReceipt, expectedValidatedAddresseses);
+            // Check balances
+            const newBalances = await erc20Wrapper.getBalancesAsync();
+            const makerAssetFillAmount = takerAssetFillAmount
+                .times(validSignedOrder.makerAssetAmount)
+                .dividedToIntegerBy(validSignedOrder.takerAssetAmount);
+            const makerFeePaid = validSignedOrder.makerFee
+                .times(makerAssetFillAmount)
+                .dividedToIntegerBy(validSignedOrder.makerAssetAmount);
+            const takerFeePaid = validSignedOrder.takerFee
+                .times(makerAssetFillAmount)
+                .dividedToIntegerBy(validSignedOrder.makerAssetAmount);
+            expect(newBalances[validMakerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[validMakerAddress][defaultMakerAssetAddress].minus(makerAssetFillAmount),
+            );
+            expect(newBalances[validMakerAddress][defaultTakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[validMakerAddress][defaultTakerAssetAddress].add(takerAssetFillAmount),
+            );
+            expect(newBalances[validMakerAddress][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[validMakerAddress][zrxToken.address].minus(makerFeePaid),
+            );
+            expect(newBalances[validTakerAddress][defaultTakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[validTakerAddress][defaultTakerAssetAddress].minus(takerAssetFillAmount),
+            );
+            expect(newBalances[validTakerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[validTakerAddress][defaultMakerAssetAddress].add(makerAssetFillAmount),
+            );
+            expect(newBalances[validTakerAddress][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[validTakerAddress][zrxToken.address].minus(takerFeePaid),
+            );
+            expect(newBalances[feeRecipientAddress][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[feeRecipientAddress][zrxToken.address].add(makerFeePaid.add(takerFeePaid)),
+            );
+        });
+        it('should revert if maker does not meet the balance threshold', async () => {
+            // Create signed order with non-valid maker address
+            const signedOrderWithBadMakerAddress = await orderFactory.newSignedOrderAsync({
+                senderAddress: erc721BalanceThresholdFilterInstance.address,
+                makerAddress: invalidAddress,
+            });
+            // Execute transaction
+            return expectTransactionFailedAsync(
+                erc721TakerBalanceThresholdWrapper.fillOrderAsync(signedOrderWithBadMakerAddress, validTakerAddress, {
+                    takerAssetFillAmount,
+                }),
+                RevertReason.AtLeastOneAddressDoesNotMeetBalanceThreshold,
+            );
+        });
+        it('should revert if taker does not meet the balance threshold', async () => {
+            return expectTransactionFailedAsync(
+                erc721NonValidBalanceThresholdWrapper.fillOrderAsync(validSignedOrder, invalidAddress, {
+                    takerAssetFillAmount,
+                }),
+                RevertReason.AtLeastOneAddressDoesNotMeetBalanceThreshold,
+            );
+        });
+    });
+
+    describe('fillOrderNoThrow', () => {
+        beforeEach(async () => {
+            erc20Balances = await erc20Wrapper.getBalancesAsync();
+            validSignedOrder = await orderFactory.newSignedOrderAsync();
+        });
+        it('should transfer the correct amounts and validate both maker/taker when both maker and taker meet the balance threshold', async () => {
+            // Execute a valid fill
+            const txReceipt = await erc721TakerBalanceThresholdWrapper.fillOrderNoThrowAsync(
+                validSignedOrder,
+                validTakerAddress,
+                {
+                    takerAssetFillAmount,
+                    // HACK(albrow): We need to hardcode the gas estimate here because
+                    // the Geth gas estimator doesn't work with the way we use
+                    // delegatecall and swallow errors.
+                    gas: 600000,
+                },
+            );
+            // Assert validated addresses
+            const expectedValidatedAddresseses = [validSignedOrder.makerAddress, validTakerAddress];
+            await assertValidatedAddressesLog(txReceipt, expectedValidatedAddresseses);
+            // Check balances
+            const newBalances = await erc20Wrapper.getBalancesAsync();
+            const makerAssetFillAmount = takerAssetFillAmount
+                .times(validSignedOrder.makerAssetAmount)
+                .dividedToIntegerBy(validSignedOrder.takerAssetAmount);
+            const makerFeePaid = validSignedOrder.makerFee
+                .times(makerAssetFillAmount)
+                .dividedToIntegerBy(validSignedOrder.makerAssetAmount);
+            const takerFeePaid = validSignedOrder.takerFee
+                .times(makerAssetFillAmount)
+                .dividedToIntegerBy(validSignedOrder.makerAssetAmount);
+            expect(newBalances[validMakerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[validMakerAddress][defaultMakerAssetAddress].minus(makerAssetFillAmount),
+            );
+            expect(newBalances[validMakerAddress][defaultTakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[validMakerAddress][defaultTakerAssetAddress].add(takerAssetFillAmount),
+            );
+            expect(newBalances[validMakerAddress][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[validMakerAddress][zrxToken.address].minus(makerFeePaid),
+            );
+            expect(newBalances[validTakerAddress][defaultTakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[validTakerAddress][defaultTakerAssetAddress].minus(takerAssetFillAmount),
+            );
+            expect(newBalances[validTakerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[validTakerAddress][defaultMakerAssetAddress].add(makerAssetFillAmount),
+            );
+            expect(newBalances[validTakerAddress][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[validTakerAddress][zrxToken.address].minus(takerFeePaid),
+            );
+            expect(newBalances[feeRecipientAddress][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[feeRecipientAddress][zrxToken.address].add(makerFeePaid.add(takerFeePaid)),
+            );
+        });
+        it('should revert if maker does not meet the balance threshold', async () => {
+            // Create signed order with non-valid maker address
+            const signedOrderWithBadMakerAddress = await orderFactory.newSignedOrderAsync({
+                senderAddress: erc721BalanceThresholdFilterInstance.address,
+                makerAddress: invalidAddress,
+            });
+            // Execute transaction
+            return expectTransactionFailedAsync(
+                erc721TakerBalanceThresholdWrapper.fillOrderNoThrowAsync(
+                    signedOrderWithBadMakerAddress,
+                    validTakerAddress,
+                    { takerAssetFillAmount },
+                ),
+                RevertReason.AtLeastOneAddressDoesNotMeetBalanceThreshold,
+            );
+        });
+        it('should revert if taker does not meet the balance threshold', async () => {
+            return expectTransactionFailedAsync(
+                erc721NonValidBalanceThresholdWrapper.fillOrderNoThrowAsync(validSignedOrder, invalidAddress, {
+                    takerAssetFillAmount,
+                }),
+                RevertReason.AtLeastOneAddressDoesNotMeetBalanceThreshold,
+            );
+        });
+    });
+
+    describe('fillOrKillOrder', () => {
+        beforeEach(async () => {
+            erc20Balances = await erc20Wrapper.getBalancesAsync();
+            validSignedOrder = await orderFactory.newSignedOrderAsync();
+        });
+        it('should transfer the correct amounts and validate both maker/taker when both maker and taker meet the balance threshold', async () => {
+            // Execute a valid fill
+            const takerAssetFillAmount_ = validSignedOrder.takerAssetAmount;
+            const txReceipt = await erc721TakerBalanceThresholdWrapper.fillOrKillOrderAsync(
+                validSignedOrder,
+                validTakerAddress,
+                { takerAssetFillAmount: takerAssetFillAmount_ },
+            );
+            // Assert validated addresses
+            const expectedValidatedAddresseses = [validSignedOrder.makerAddress, validTakerAddress];
+            await assertValidatedAddressesLog(txReceipt, expectedValidatedAddresseses);
+            // Check balances
+            const newBalances = await erc20Wrapper.getBalancesAsync();
+            const makerAssetFillAmount = takerAssetFillAmount_
+                .times(validSignedOrder.makerAssetAmount)
+                .dividedToIntegerBy(validSignedOrder.takerAssetAmount);
+            const makerFeePaid = validSignedOrder.makerFee
+                .times(makerAssetFillAmount)
+                .dividedToIntegerBy(validSignedOrder.makerAssetAmount);
+            const takerFeePaid = validSignedOrder.takerFee
+                .times(makerAssetFillAmount)
+                .dividedToIntegerBy(validSignedOrder.makerAssetAmount);
+            expect(newBalances[validMakerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[validMakerAddress][defaultMakerAssetAddress].minus(makerAssetFillAmount),
+            );
+            expect(newBalances[validMakerAddress][defaultTakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[validMakerAddress][defaultTakerAssetAddress].add(takerAssetFillAmount_),
+            );
+            expect(newBalances[validMakerAddress][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[validMakerAddress][zrxToken.address].minus(makerFeePaid),
+            );
+            expect(newBalances[validTakerAddress][defaultTakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[validTakerAddress][defaultTakerAssetAddress].minus(takerAssetFillAmount_),
+            );
+            expect(newBalances[validTakerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[validTakerAddress][defaultMakerAssetAddress].add(makerAssetFillAmount),
+            );
+            expect(newBalances[validTakerAddress][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[validTakerAddress][zrxToken.address].minus(takerFeePaid),
+            );
+            expect(newBalances[feeRecipientAddress][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[feeRecipientAddress][zrxToken.address].add(makerFeePaid.add(takerFeePaid)),
+            );
+        });
+        it('should revert if maker does not meet the balance threshold', async () => {
+            // Create signed order with non-valid maker address
+            const signedOrderWithBadMakerAddress = await orderFactory.newSignedOrderAsync({
+                senderAddress: erc721BalanceThresholdFilterInstance.address,
+                makerAddress: invalidAddress,
+            });
+            // Execute transaction
+            return expectTransactionFailedAsync(
+                erc721TakerBalanceThresholdWrapper.fillOrKillOrderAsync(
+                    signedOrderWithBadMakerAddress,
+                    validTakerAddress,
+                    { takerAssetFillAmount },
+                ),
+                RevertReason.AtLeastOneAddressDoesNotMeetBalanceThreshold,
+            );
+        });
+        it('should revert if taker does not meet the balance threshold', async () => {
+            return expectTransactionFailedAsync(
+                erc721NonValidBalanceThresholdWrapper.fillOrKillOrderAsync(validSignedOrder, invalidAddress, {
+                    takerAssetFillAmount,
+                }),
+                RevertReason.AtLeastOneAddressDoesNotMeetBalanceThreshold,
+            );
+        });
+        it('should revert if takerAssetFillAmount is not fully filled', async () => {
+            const tooBigTakerAssetFillAmount = validSignedOrder.takerAssetAmount.times(2);
+            return expectTransactionFailedAsync(
+                erc721TakerBalanceThresholdWrapper.fillOrKillOrderAsync(validSignedOrder, validTakerAddress, {
+                    takerAssetFillAmount: tooBigTakerAssetFillAmount,
+                }),
+                RevertReason.FailedExecution,
+            );
+        });
+    });
+
+    describe('marketSellOrders', () => {
+        beforeEach(async () => {
+            erc20Balances = await erc20Wrapper.getBalancesAsync();
+            validSignedOrder = await orderFactory.newSignedOrderAsync();
+            validSignedOrder2 = await orderFactory2.newSignedOrderAsync();
+        });
+        it('should transfer the correct amounts and validate both makers/taker when both makers and taker meet the balance threshold', async () => {
+            // Execute a valid fill
+            const orders = [validSignedOrder, validSignedOrder2];
+            const cumulativeTakerAssetFillAmount = validSignedOrder.takerAssetAmount.plus(takerAssetFillAmount);
+            const txReceipt = await erc721TakerBalanceThresholdWrapper.marketSellOrdersAsync(
+                orders,
+                validTakerAddress,
+                { takerAssetFillAmount: cumulativeTakerAssetFillAmount },
+            );
+            // Assert validated addresses
+            const expectedValidatedAddresseses = [
+                validSignedOrder.makerAddress,
+                validSignedOrder2.makerAddress,
+                validTakerAddress,
+            ];
+            await assertValidatedAddressesLog(txReceipt, expectedValidatedAddresseses);
+            // Check balances
+            const newBalances = await erc20Wrapper.getBalancesAsync();
+            const makerAssetFillAmount2 = takerAssetFillAmount
+                .times(validSignedOrder.makerAssetAmount)
+                .dividedToIntegerBy(validSignedOrder.takerAssetAmount);
+            const makerFeePaid2 = validSignedOrder2.makerFee
+                .times(makerAssetFillAmount2)
+                .dividedToIntegerBy(validSignedOrder2.makerAssetAmount);
+            const takerFeePaid2 = validSignedOrder2.takerFee
+                .times(makerAssetFillAmount2)
+                .dividedToIntegerBy(validSignedOrder2.makerAssetAmount);
+            const takerFeePaid = validSignedOrder.takerFee.plus(takerFeePaid2);
+            const cumulativeMakerAssetFillAmount = validSignedOrder.makerAssetAmount.plus(makerAssetFillAmount2);
+            // Maker #1
+            expect(newBalances[validMakerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[validMakerAddress][defaultMakerAssetAddress].minus(validSignedOrder.makerAssetAmount),
+            );
+            expect(newBalances[validMakerAddress][defaultTakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[validMakerAddress][defaultTakerAssetAddress].add(validSignedOrder.takerAssetAmount),
+            );
+            expect(newBalances[validMakerAddress][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[validMakerAddress][zrxToken.address].minus(validSignedOrder.makerFee),
+            );
+            // Maker #2
+            expect(newBalances[validMakerAddress2][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[validMakerAddress2][defaultMakerAssetAddress].minus(makerAssetFillAmount2),
+            );
+            expect(newBalances[validMakerAddress2][defaultTakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[validMakerAddress2][defaultTakerAssetAddress].add(takerAssetFillAmount),
+            );
+            expect(newBalances[validMakerAddress2][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[validMakerAddress2][zrxToken.address].minus(makerFeePaid2),
+            );
+            // Taker
+            expect(newBalances[validTakerAddress][defaultTakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[validTakerAddress][defaultTakerAssetAddress].minus(cumulativeTakerAssetFillAmount),
+            );
+            expect(newBalances[validTakerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[validTakerAddress][defaultMakerAssetAddress].add(cumulativeMakerAssetFillAmount),
+            );
+            expect(newBalances[validTakerAddress][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[validTakerAddress][zrxToken.address].minus(takerFeePaid),
+            );
+            // Fee recipient
+            expect(newBalances[feeRecipientAddress][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[feeRecipientAddress][zrxToken.address]
+                    .add(validSignedOrder.makerFee)
+                    .add(makerFeePaid2)
+                    .add(takerFeePaid),
+            );
+        });
+        it('should revert if one maker does not meet the balance threshold', async () => {
+            // Create order set with one non-valid maker address
+            const signedOrderWithBadMakerAddress = await orderFactory.newSignedOrderAsync({
+                makerAddress: invalidAddress,
+            });
+            const orders = [validSignedOrder, signedOrderWithBadMakerAddress];
+            // Execute transaction
+            return expectTransactionFailedAsync(
+                erc721TakerBalanceThresholdWrapper.marketSellOrdersAsync(orders, validTakerAddress, {
+                    takerAssetFillAmount,
+                }),
+                RevertReason.AtLeastOneAddressDoesNotMeetBalanceThreshold,
+            );
+        });
+        it('should revert if taker does not meet the balance threshold', async () => {
+            const orders = [validSignedOrder, validSignedOrder2];
+            return expectTransactionFailedAsync(
+                erc721NonValidBalanceThresholdWrapper.marketSellOrdersAsync(orders, invalidAddress, {
+                    takerAssetFillAmount,
+                }),
+                RevertReason.AtLeastOneAddressDoesNotMeetBalanceThreshold,
+            );
+        });
+    });
+
+    describe('marketSellOrdersNoThrow', () => {
+        beforeEach(async () => {
+            erc20Balances = await erc20Wrapper.getBalancesAsync();
+            validSignedOrder = await orderFactory.newSignedOrderAsync();
+            validSignedOrder2 = await orderFactory2.newSignedOrderAsync();
+        });
+        it('should transfer the correct amounts and validate both makers/taker when both makers and taker meet the balance threshold', async () => {
+            // Execute a valid fill
+            const orders = [validSignedOrder, validSignedOrder2];
+            const cumulativeTakerAssetFillAmount = validSignedOrder.takerAssetAmount.plus(takerAssetFillAmount);
+            const txReceipt = await erc721TakerBalanceThresholdWrapper.marketSellOrdersNoThrowAsync(
+                orders,
+                validTakerAddress,
+                {
+                    takerAssetFillAmount: cumulativeTakerAssetFillAmount,
+                    // HACK(albrow): We need to hardcode the gas estimate here because
+                    // the Geth gas estimator doesn't work with the way we use
+                    // delegatecall and swallow errors.
+                    gas: 600000,
+                },
+            );
+            // Assert validated addresses
+            const expectedValidatedAddresseses = [
+                validSignedOrder.makerAddress,
+                validSignedOrder2.makerAddress,
+                validTakerAddress,
+            ];
+            await assertValidatedAddressesLog(txReceipt, expectedValidatedAddresseses);
+            // Check balances
+            const newBalances = await erc20Wrapper.getBalancesAsync();
+            const makerAssetFillAmount2 = takerAssetFillAmount
+                .times(validSignedOrder.makerAssetAmount)
+                .dividedToIntegerBy(validSignedOrder.takerAssetAmount);
+            const makerFeePaid2 = validSignedOrder2.makerFee
+                .times(makerAssetFillAmount2)
+                .dividedToIntegerBy(validSignedOrder2.makerAssetAmount);
+            const takerFeePaid2 = validSignedOrder2.takerFee
+                .times(makerAssetFillAmount2)
+                .dividedToIntegerBy(validSignedOrder2.makerAssetAmount);
+            const takerFeePaid = validSignedOrder.takerFee.plus(takerFeePaid2);
+            const cumulativeMakerAssetFillAmount = validSignedOrder.makerAssetAmount.plus(makerAssetFillAmount2);
+            // Maker #1
+            expect(newBalances[validMakerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[validMakerAddress][defaultMakerAssetAddress].minus(validSignedOrder.makerAssetAmount),
+            );
+            expect(newBalances[validMakerAddress][defaultTakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[validMakerAddress][defaultTakerAssetAddress].add(validSignedOrder.takerAssetAmount),
+            );
+            expect(newBalances[validMakerAddress][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[validMakerAddress][zrxToken.address].minus(validSignedOrder.makerFee),
+            );
+            // Maker #2
+            expect(newBalances[validMakerAddress2][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[validMakerAddress2][defaultMakerAssetAddress].minus(makerAssetFillAmount2),
+            );
+            expect(newBalances[validMakerAddress2][defaultTakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[validMakerAddress2][defaultTakerAssetAddress].add(takerAssetFillAmount),
+            );
+            expect(newBalances[validMakerAddress2][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[validMakerAddress2][zrxToken.address].minus(makerFeePaid2),
+            );
+            // Taker
+            expect(newBalances[validTakerAddress][defaultTakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[validTakerAddress][defaultTakerAssetAddress].minus(cumulativeTakerAssetFillAmount),
+            );
+            expect(newBalances[validTakerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[validTakerAddress][defaultMakerAssetAddress].add(cumulativeMakerAssetFillAmount),
+            );
+            expect(newBalances[validTakerAddress][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[validTakerAddress][zrxToken.address].minus(takerFeePaid),
+            );
+            // Fee recipient
+            expect(newBalances[feeRecipientAddress][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[feeRecipientAddress][zrxToken.address]
+                    .add(validSignedOrder.makerFee)
+                    .add(makerFeePaid2)
+                    .add(takerFeePaid),
+            );
+        });
+        it('should revert if one maker does not meet the balance threshold', async () => {
+            // Create order set with one non-valid maker address
+            const signedOrderWithBadMakerAddress = await orderFactory.newSignedOrderAsync({
+                makerAddress: invalidAddress,
+            });
+            const orders = [validSignedOrder, signedOrderWithBadMakerAddress];
+            // Execute transaction
+            return expectTransactionFailedAsync(
+                erc721TakerBalanceThresholdWrapper.marketSellOrdersNoThrowAsync(orders, validTakerAddress, {
+                    takerAssetFillAmount,
+                }),
+                RevertReason.AtLeastOneAddressDoesNotMeetBalanceThreshold,
+            );
+        });
+        it('should revert if taker does not meet the balance threshold', async () => {
+            const orders = [validSignedOrder, validSignedOrder2];
+            return expectTransactionFailedAsync(
+                erc721NonValidBalanceThresholdWrapper.marketSellOrdersNoThrowAsync(orders, invalidAddress, {
+                    takerAssetFillAmount,
+                }),
+                RevertReason.AtLeastOneAddressDoesNotMeetBalanceThreshold,
+            );
+        });
+    });
+
+    describe('marketBuyOrders', () => {
+        beforeEach(async () => {
+            erc20Balances = await erc20Wrapper.getBalancesAsync();
+            validSignedOrder = await orderFactory.newSignedOrderAsync();
+            validSignedOrder2 = await orderFactory2.newSignedOrderAsync();
+        });
+        it('should transfer the correct amounts and validate both makers/taker when both makers and taker meet the balance threshold', async () => {
+            // Execute a valid fill
+            const orders = [validSignedOrder, validSignedOrder2];
+            const cumulativeTakerAssetFillAmount = validSignedOrder.takerAssetAmount.plus(takerAssetFillAmount);
+            const makerAssetFillAmount2 = takerAssetFillAmount
+                .times(validSignedOrder.makerAssetAmount)
+                .dividedToIntegerBy(validSignedOrder.takerAssetAmount);
+            const cumulativeMakerAssetFillAmount = validSignedOrder.makerAssetAmount.plus(makerAssetFillAmount2);
+            const txReceipt = await erc721TakerBalanceThresholdWrapper.marketBuyOrdersAsync(orders, validTakerAddress, {
+                makerAssetFillAmount: cumulativeMakerAssetFillAmount,
+            });
+            // Assert validated addresses
+            const expectedValidatedAddresseses = [
+                validSignedOrder.makerAddress,
+                validSignedOrder2.makerAddress,
+                validTakerAddress,
+            ];
+            await assertValidatedAddressesLog(txReceipt, expectedValidatedAddresseses);
+            // Check balances
+            const newBalances = await erc20Wrapper.getBalancesAsync();
+            const makerFeePaid2 = validSignedOrder2.makerFee
+                .times(makerAssetFillAmount2)
+                .dividedToIntegerBy(validSignedOrder2.makerAssetAmount);
+            const takerFeePaid2 = validSignedOrder2.takerFee
+                .times(makerAssetFillAmount2)
+                .dividedToIntegerBy(validSignedOrder2.makerAssetAmount);
+            const takerFeePaid = validSignedOrder.takerFee.plus(takerFeePaid2);
+            // Maker #1
+            expect(newBalances[validMakerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[validMakerAddress][defaultMakerAssetAddress].minus(validSignedOrder.makerAssetAmount),
+            );
+            expect(newBalances[validMakerAddress][defaultTakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[validMakerAddress][defaultTakerAssetAddress].add(validSignedOrder.takerAssetAmount),
+            );
+            expect(newBalances[validMakerAddress][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[validMakerAddress][zrxToken.address].minus(validSignedOrder.makerFee),
+            );
+            // Maker #2
+            expect(newBalances[validMakerAddress2][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[validMakerAddress2][defaultMakerAssetAddress].minus(makerAssetFillAmount2),
+            );
+            expect(newBalances[validMakerAddress2][defaultTakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[validMakerAddress2][defaultTakerAssetAddress].add(takerAssetFillAmount),
+            );
+            expect(newBalances[validMakerAddress2][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[validMakerAddress2][zrxToken.address].minus(makerFeePaid2),
+            );
+            // Taker
+            expect(newBalances[validTakerAddress][defaultTakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[validTakerAddress][defaultTakerAssetAddress].minus(cumulativeTakerAssetFillAmount),
+            );
+            expect(newBalances[validTakerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[validTakerAddress][defaultMakerAssetAddress].add(cumulativeMakerAssetFillAmount),
+            );
+            expect(newBalances[validTakerAddress][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[validTakerAddress][zrxToken.address].minus(takerFeePaid),
+            );
+            // Fee recipient
+            expect(newBalances[feeRecipientAddress][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[feeRecipientAddress][zrxToken.address]
+                    .add(validSignedOrder.makerFee)
+                    .add(makerFeePaid2)
+                    .add(takerFeePaid),
+            );
+        });
+        it('should revert if one maker does not meet the balance threshold', async () => {
+            // Create order set with one non-valid maker address
+            const signedOrderWithBadMakerAddress = await orderFactory.newSignedOrderAsync({
+                makerAddress: invalidAddress,
+            });
+            const orders = [validSignedOrder, signedOrderWithBadMakerAddress];
+            // Execute transaction
+            const dummyMakerAssetFillAmount = new BigNumber(0);
+            return expectTransactionFailedAsync(
+                erc721TakerBalanceThresholdWrapper.marketBuyOrdersAsync(orders, validTakerAddress, {
+                    makerAssetFillAmount: dummyMakerAssetFillAmount,
+                }),
+                RevertReason.AtLeastOneAddressDoesNotMeetBalanceThreshold,
+            );
+        });
+        it('should revert if taker does not meet the balance threshold', async () => {
+            const orders = [validSignedOrder, validSignedOrder2];
+            const dummyMakerAssetFillAmount = new BigNumber(0);
+            return expectTransactionFailedAsync(
+                erc721NonValidBalanceThresholdWrapper.marketBuyOrdersAsync(orders, invalidAddress, {
+                    makerAssetFillAmount: dummyMakerAssetFillAmount,
+                }),
+                RevertReason.AtLeastOneAddressDoesNotMeetBalanceThreshold,
+            );
+        });
+    });
+
+    describe('marketBuyOrdersNoThrowAsync', () => {
+        beforeEach(async () => {
+            erc20Balances = await erc20Wrapper.getBalancesAsync();
+            validSignedOrder = await orderFactory.newSignedOrderAsync();
+            validSignedOrder2 = await orderFactory2.newSignedOrderAsync();
+        });
+        it('should transfer the correct amounts and validate both makers/taker when both makers and taker meet the balance threshold', async () => {
+            // Execute a valid fill
+            const orders = [validSignedOrder, validSignedOrder2];
+            const cumulativeTakerAssetFillAmount = validSignedOrder.takerAssetAmount.plus(takerAssetFillAmount);
+            const makerAssetFillAmount2 = takerAssetFillAmount
+                .times(validSignedOrder.makerAssetAmount)
+                .dividedToIntegerBy(validSignedOrder.takerAssetAmount);
+            const cumulativeMakerAssetFillAmount = validSignedOrder.makerAssetAmount.plus(makerAssetFillAmount2);
+            const txReceipt = await erc721TakerBalanceThresholdWrapper.marketBuyOrdersNoThrowAsync(
+                orders,
+                validTakerAddress,
+                {
+                    makerAssetFillAmount: cumulativeMakerAssetFillAmount,
+                    // HACK(albrow): We need to hardcode the gas estimate here because
+                    // the Geth gas estimator doesn't work with the way we use
+                    // delegatecall and swallow errors.
+                    gas: 600000,
+                },
+            );
+            // Assert validated addresses
+            const expectedValidatedAddresseses = [
+                validSignedOrder.makerAddress,
+                validSignedOrder2.makerAddress,
+                validTakerAddress,
+            ];
+            await assertValidatedAddressesLog(txReceipt, expectedValidatedAddresseses);
+            // Check balances
+            const newBalances = await erc20Wrapper.getBalancesAsync();
+            const makerFeePaid2 = validSignedOrder2.makerFee
+                .times(makerAssetFillAmount2)
+                .dividedToIntegerBy(validSignedOrder2.makerAssetAmount);
+            const takerFeePaid2 = validSignedOrder2.takerFee
+                .times(makerAssetFillAmount2)
+                .dividedToIntegerBy(validSignedOrder2.makerAssetAmount);
+            const takerFeePaid = validSignedOrder.takerFee.plus(takerFeePaid2);
+            // Maker #1
+            expect(newBalances[validMakerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[validMakerAddress][defaultMakerAssetAddress].minus(validSignedOrder.makerAssetAmount),
+            );
+            expect(newBalances[validMakerAddress][defaultTakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[validMakerAddress][defaultTakerAssetAddress].add(validSignedOrder.takerAssetAmount),
+            );
+            expect(newBalances[validMakerAddress][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[validMakerAddress][zrxToken.address].minus(validSignedOrder.makerFee),
+            );
+            // Maker #2
+            expect(newBalances[validMakerAddress2][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[validMakerAddress2][defaultMakerAssetAddress].minus(makerAssetFillAmount2),
+            );
+            expect(newBalances[validMakerAddress2][defaultTakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[validMakerAddress2][defaultTakerAssetAddress].add(takerAssetFillAmount),
+            );
+            expect(newBalances[validMakerAddress2][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[validMakerAddress2][zrxToken.address].minus(makerFeePaid2),
+            );
+            // Taker
+            expect(newBalances[validTakerAddress][defaultTakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[validTakerAddress][defaultTakerAssetAddress].minus(cumulativeTakerAssetFillAmount),
+            );
+            expect(newBalances[validTakerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[validTakerAddress][defaultMakerAssetAddress].add(cumulativeMakerAssetFillAmount),
+            );
+            expect(newBalances[validTakerAddress][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[validTakerAddress][zrxToken.address].minus(takerFeePaid),
+            );
+            // Fee recipient
+            expect(newBalances[feeRecipientAddress][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[feeRecipientAddress][zrxToken.address]
+                    .add(validSignedOrder.makerFee)
+                    .add(makerFeePaid2)
+                    .add(takerFeePaid),
+            );
+        });
+        it('should revert if one maker does not meet the balance threshold', async () => {
+            // Create order set with one non-valid maker address
+            const signedOrderWithBadMakerAddress = await orderFactory.newSignedOrderAsync({
+                makerAddress: invalidAddress,
+            });
+            const orders = [validSignedOrder, signedOrderWithBadMakerAddress];
+            // Execute transaction
+            const dummyMakerAssetFillAmount = new BigNumber(0);
+            return expectTransactionFailedAsync(
+                erc721TakerBalanceThresholdWrapper.marketBuyOrdersNoThrowAsync(orders, validTakerAddress, {
+                    makerAssetFillAmount: dummyMakerAssetFillAmount,
+                }),
+                RevertReason.AtLeastOneAddressDoesNotMeetBalanceThreshold,
+            );
+        });
+        it('should revert if taker does not meet the balance threshold', async () => {
+            const orders = [validSignedOrder, validSignedOrder2];
+            const dummyMakerAssetFillAmount = new BigNumber(0);
+            return expectTransactionFailedAsync(
+                erc721NonValidBalanceThresholdWrapper.marketBuyOrdersNoThrowAsync(orders, invalidAddress, {
+                    makerAssetFillAmount: dummyMakerAssetFillAmount,
+                }),
+                RevertReason.AtLeastOneAddressDoesNotMeetBalanceThreshold,
+            );
+        });
+    });
+
+    describe('matchOrders', () => {
+        beforeEach(async () => {
+            erc20Balances = await erc20Wrapper.getBalancesAsync();
+            validSignedOrder = await orderFactory.newSignedOrderAsync();
+            validSignedOrder2 = await orderFactory2.newSignedOrderAsync();
+        });
+        it('Should transfer correct amounts when both makers and taker meet the balance threshold', async () => {
+            // Test values/results taken from Match Orders test:
+            // 'Should transfer correct amounts when right order is fully filled and values pass isRoundingErrorFloor but fail isRoundingErrorCeil'
+            // Create orders to match
+            const signedOrderLeft = await orderFactory.newSignedOrderAsync({
+                makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(17), 0),
+                takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(98), 0),
+                makerFee: Web3Wrapper.toBaseUnitAmount(new BigNumber(1), 18),
+                takerFee: Web3Wrapper.toBaseUnitAmount(new BigNumber(1), 18),
+                feeRecipientAddress,
+            });
+            const signedOrderRight = await orderFactory2.newSignedOrderAsync({
+                makerAssetData: assetDataUtils.encodeERC20AssetData(defaultTakerAssetAddress),
+                takerAssetData: assetDataUtils.encodeERC20AssetData(defaultMakerAssetAddress),
+                makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(75), 0),
+                takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(13), 0),
+                makerFee: Web3Wrapper.toBaseUnitAmount(new BigNumber(1), 18),
+                takerFee: Web3Wrapper.toBaseUnitAmount(new BigNumber(1), 18),
+                feeRecipientAddress,
+            });
+            // Compute expected transfer amounts
+            const expectedTransferAmounts = {
+                // Left Maker
+                amountSoldByLeftMaker: Web3Wrapper.toBaseUnitAmount(new BigNumber(13), 0),
+                amountBoughtByLeftMaker: Web3Wrapper.toBaseUnitAmount(new BigNumber(75), 0),
+                feePaidByLeftMaker: Web3Wrapper.toBaseUnitAmount(new BigNumber('76.4705882352941176'), 16), // 76.47%
+                // Right Maker
+                amountSoldByRightMaker: Web3Wrapper.toBaseUnitAmount(new BigNumber(75), 0),
+                amountBoughtByRightMaker: Web3Wrapper.toBaseUnitAmount(new BigNumber(13), 0),
+                feePaidByRightMaker: Web3Wrapper.toBaseUnitAmount(new BigNumber(100), 16), // 100%
+                // Taker
+                amountReceivedByTaker: Web3Wrapper.toBaseUnitAmount(new BigNumber(0), 0),
+                feePaidByTakerLeft: Web3Wrapper.toBaseUnitAmount(new BigNumber('76.5306122448979591'), 16), // 76.53%
+                feePaidByTakerRight: Web3Wrapper.toBaseUnitAmount(new BigNumber(100), 16), // 100%
+            };
+            const txReceipt = await erc721TakerBalanceThresholdWrapper.matchOrdersAsync(
+                signedOrderLeft,
+                signedOrderRight,
+                validTakerAddress,
+            );
+            // Assert validated addresses
+            const expectedValidatedAddresseses = [
+                signedOrderLeft.makerAddress,
+                signedOrderRight.makerAddress,
+                validTakerAddress,
+            ];
+            await assertValidatedAddressesLog(txReceipt, expectedValidatedAddresseses);
+            // Check balances
+            const newBalances = await erc20Wrapper.getBalancesAsync();
+            expect(
+                newBalances[signedOrderLeft.makerAddress][defaultMakerAssetAddress],
+                'Checking left maker egress ERC20 account balance',
+            ).to.be.bignumber.equal(
+                erc20Balances[signedOrderLeft.makerAddress][defaultMakerAssetAddress].sub(
+                    expectedTransferAmounts.amountSoldByLeftMaker,
+                ),
+            );
+            expect(
+                newBalances[signedOrderRight.makerAddress][defaultTakerAssetAddress],
+                'Checking right maker ingress ERC20 account balance',
+            ).to.be.bignumber.equal(
+                erc20Balances[signedOrderRight.makerAddress][defaultTakerAssetAddress].sub(
+                    expectedTransferAmounts.amountSoldByRightMaker,
+                ),
+            );
+            expect(
+                newBalances[validTakerAddress][defaultMakerAssetAddress],
+                'Checking taker ingress ERC20 account balance',
+            ).to.be.bignumber.equal(
+                erc20Balances[validTakerAddress][defaultMakerAssetAddress].add(
+                    expectedTransferAmounts.amountReceivedByTaker,
+                ),
+            );
+            expect(
+                newBalances[signedOrderLeft.makerAddress][defaultTakerAssetAddress],
+                'Checking left maker ingress ERC20 account balance',
+            ).to.be.bignumber.equal(
+                erc20Balances[signedOrderLeft.makerAddress][defaultTakerAssetAddress].add(
+                    expectedTransferAmounts.amountBoughtByLeftMaker,
+                ),
+            );
+            expect(
+                newBalances[signedOrderRight.makerAddress][defaultMakerAssetAddress],
+                'Checking right maker egress ERC20 account balance',
+            ).to.be.bignumber.equal(
+                erc20Balances[signedOrderRight.makerAddress][defaultMakerAssetAddress].add(
+                    expectedTransferAmounts.amountBoughtByRightMaker,
+                ),
+            );
+            // Paid fees
+            expect(
+                newBalances[signedOrderLeft.makerAddress][zrxToken.address],
+                'Checking left maker egress ERC20 account fees',
+            ).to.be.bignumber.equal(
+                erc20Balances[signedOrderLeft.makerAddress][zrxToken.address].minus(
+                    expectedTransferAmounts.feePaidByLeftMaker,
+                ),
+            );
+            expect(
+                newBalances[signedOrderRight.makerAddress][zrxToken.address],
+                'Checking right maker egress ERC20 account fees',
+            ).to.be.bignumber.equal(
+                erc20Balances[signedOrderRight.makerAddress][zrxToken.address].minus(
+                    expectedTransferAmounts.feePaidByRightMaker,
+                ),
+            );
+            expect(
+                newBalances[validTakerAddress][zrxToken.address],
+                'Checking taker egress ERC20 account fees',
+            ).to.be.bignumber.equal(
+                erc20Balances[validTakerAddress][zrxToken.address]
+                    .minus(expectedTransferAmounts.feePaidByTakerLeft)
+                    .sub(expectedTransferAmounts.feePaidByTakerRight),
+            );
+            // Received fees
+            expect(
+                newBalances[signedOrderLeft.feeRecipientAddress][zrxToken.address],
+                'Checking left fee recipient ingress ERC20 account fees',
+            ).to.be.bignumber.equal(
+                erc20Balances[feeRecipientAddress][zrxToken.address]
+                    .add(expectedTransferAmounts.feePaidByLeftMaker)
+                    .add(expectedTransferAmounts.feePaidByRightMaker)
+                    .add(expectedTransferAmounts.feePaidByTakerLeft)
+                    .add(expectedTransferAmounts.feePaidByTakerRight),
+            );
+        });
+        it('should revert if left maker does not meet the balance threshold', async () => {
+            // Create signed order with non-valid maker address
+            const signedOrderWithBadMakerAddress = await orderFactory.newSignedOrderAsync({
+                senderAddress: erc721BalanceThresholdFilterInstance.address,
+                makerAddress: invalidAddress,
+            });
+            // Execute transaction
+            return expectTransactionFailedAsync(
+                erc721TakerBalanceThresholdWrapper.matchOrdersAsync(
+                    validSignedOrder,
+                    signedOrderWithBadMakerAddress,
+                    validTakerAddress,
+                ),
+                RevertReason.AtLeastOneAddressDoesNotMeetBalanceThreshold,
+            );
+        });
+        it('should revert if right maker does not meet the balance threshold', async () => {
+            // Create signed order with non-valid maker address
+            const signedOrderWithBadMakerAddress = await orderFactory.newSignedOrderAsync({
+                senderAddress: erc721BalanceThresholdFilterInstance.address,
+                makerAddress: invalidAddress,
+            });
+            // Execute transaction
+            return expectTransactionFailedAsync(
+                erc721TakerBalanceThresholdWrapper.matchOrdersAsync(
+                    signedOrderWithBadMakerAddress,
+                    validSignedOrder,
+                    validTakerAddress,
+                ),
+                RevertReason.AtLeastOneAddressDoesNotMeetBalanceThreshold,
+            );
+        });
+        it('should revert if taker does not meet the balance threshold', async () => {
+            return expectTransactionFailedAsync(
+                erc721NonValidBalanceThresholdWrapper.matchOrdersAsync(
+                    validSignedOrder,
+                    validSignedOrder,
+                    invalidAddress,
+                ),
+                RevertReason.AtLeastOneAddressDoesNotMeetBalanceThreshold,
+            );
+        });
+    });
+
+    describe('cancelOrder', () => {
+        beforeEach(async () => {
+            erc20Balances = await erc20Wrapper.getBalancesAsync();
+            validSignedOrder = await orderFactory.newSignedOrderAsync();
+            validSignedOrder2 = await orderFactory2.newSignedOrderAsync();
+        });
+        it('Should successfully cancel order if maker meets balance threshold', async () => {
+            // Verify order is not cancelled
+            const orderInfoBeforeCancelling = await erc721MakerBalanceThresholdWrapper.getOrderInfoAsync(
+                validSignedOrder,
+            );
+            expect(orderInfoBeforeCancelling.orderStatus).to.be.equal(OrderStatus.FILLABLE);
+            // Cancel
+            const txReceipt = await erc721MakerBalanceThresholdWrapper.cancelOrderAsync(
+                validSignedOrder,
+                validSignedOrder.makerAddress,
+            );
+            // Assert validated addresses
+            const expectedValidatedAddresseses: string[] = [];
+            await assertValidatedAddressesLog(txReceipt, expectedValidatedAddresseses);
+            // Check that order was cancelled
+            const orderInfoAfterCancelling = await erc721MakerBalanceThresholdWrapper.getOrderInfoAsync(
+                validSignedOrder,
+            );
+            expect(orderInfoAfterCancelling.orderStatus).to.be.equal(OrderStatus.CANCELLED);
+        });
+        it('Should successfully cancel order if maker does not meet balance threshold', async () => {
+            // Create order where maker does not meet balance threshold
+            const signedOrderWithBadMakerAddress = await invalidOrderFactory.newSignedOrderAsync({});
+            // Verify order is not cancelled
+            const orderInfoBeforeCancelling = await erc721NonValidBalanceThresholdWrapper.getOrderInfoAsync(
+                signedOrderWithBadMakerAddress,
+            );
+            expect(orderInfoBeforeCancelling.orderStatus).to.be.equal(OrderStatus.FILLABLE);
+            // Cancel
+            const txReceipt = await erc721NonValidBalanceThresholdWrapper.cancelOrderAsync(
+                signedOrderWithBadMakerAddress,
+                signedOrderWithBadMakerAddress.makerAddress,
+            );
+            // Assert validated addresses
+            const expectedValidatedAddresseses: string[] = [];
+            await assertValidatedAddressesLog(txReceipt, expectedValidatedAddresseses);
+            // Check that order was cancelled
+            const orderInfoAfterCancelling = await erc721MakerBalanceThresholdWrapper.getOrderInfoAsync(
+                signedOrderWithBadMakerAddress,
+            );
+            expect(orderInfoAfterCancelling.orderStatus).to.be.equal(OrderStatus.CANCELLED);
+        });
+    });
+
+    describe('batchCancelOrders', () => {
+        beforeEach(async () => {
+            erc20Balances = await erc20Wrapper.getBalancesAsync();
+        });
+        it('Should successfully batch cancel orders if maker meets balance threshold', async () => {
+            // Create orders to cancel
+            const validSignedOrders = [
+                await orderFactory.newSignedOrderAsync(),
+                await orderFactory.newSignedOrderAsync(),
+                await orderFactory.newSignedOrderAsync(),
+            ];
+            // Verify orders are not cancelled
+            _.each(validSignedOrders, async signedOrder => {
+                const orderInfoBeforeCancelling = await erc721MakerBalanceThresholdWrapper.getOrderInfoAsync(
+                    signedOrder,
+                );
+                return expect(orderInfoBeforeCancelling.orderStatus).to.be.equal(OrderStatus.FILLABLE);
+            });
+            // Cancel
+            const txReceipt = await erc721MakerBalanceThresholdWrapper.batchCancelOrdersAsync(
+                validSignedOrders,
+                validSignedOrders[0].makerAddress,
+            );
+            // Assert validated addresses
+            const expectedValidatedAddresseses: string[] = [];
+            await assertValidatedAddressesLog(txReceipt, expectedValidatedAddresseses);
+            // Check that order was cancelled
+            _.each(validSignedOrders, async signedOrder => {
+                const orderInfoAfterCancelling = await erc721MakerBalanceThresholdWrapper.getOrderInfoAsync(
+                    signedOrder,
+                );
+                return expect(orderInfoAfterCancelling.orderStatus).to.be.equal(OrderStatus.CANCELLED);
+            });
+        });
+        it('Should successfully batch cancel order if maker does not meet balance threshold', async () => {
+            // Create orders to cancel
+            const invalidSignedOrders = [
+                await invalidOrderFactory.newSignedOrderAsync(),
+                await invalidOrderFactory.newSignedOrderAsync(),
+                await invalidOrderFactory.newSignedOrderAsync(),
+            ];
+            // Verify orders are not cancelled
+            _.each(invalidSignedOrders, async signedOrder => {
+                const orderInfoBeforeCancelling = await erc721NonValidBalanceThresholdWrapper.getOrderInfoAsync(
+                    signedOrder,
+                );
+                return expect(orderInfoBeforeCancelling.orderStatus).to.be.equal(OrderStatus.FILLABLE);
+            });
+            // Cancel
+            const txReceipt = await erc721NonValidBalanceThresholdWrapper.batchCancelOrdersAsync(
+                invalidSignedOrders,
+                invalidAddress,
+            );
+            // Assert validated addresses
+            const expectedValidatedAddresseses: string[] = [];
+            await assertValidatedAddressesLog(txReceipt, expectedValidatedAddresseses);
+            // Check that order was cancelled
+            _.each(invalidSignedOrders, async signedOrder => {
+                const orderInfoAfterCancelling = await erc721NonValidBalanceThresholdWrapper.getOrderInfoAsync(
+                    signedOrder,
+                );
+                return expect(orderInfoAfterCancelling.orderStatus).to.be.equal(OrderStatus.CANCELLED);
+            });
+        });
+    });
+
+    describe('cancelOrdersUpTo', () => {
+        beforeEach(async () => {
+            erc20Balances = await erc20Wrapper.getBalancesAsync();
+        });
+        it('Should successfully batch cancel orders if maker meets balance threshold', async () => {
+            // Create orders to cancel
+            const validSignedOrders = [
+                await orderFactory.newSignedOrderAsync({ salt: new BigNumber(0) }),
+                await orderFactory.newSignedOrderAsync({ salt: new BigNumber(1) }),
+                await orderFactory.newSignedOrderAsync({ salt: new BigNumber(2) }),
+            ];
+            // Verify orders are not cancelled
+            _.each(validSignedOrders, async signedOrder => {
+                const orderInfoBeforeCancelling = await erc721MakerBalanceThresholdWrapper.getOrderInfoAsync(
+                    signedOrder,
+                );
+                return expect(orderInfoBeforeCancelling.orderStatus).to.be.equal(OrderStatus.FILLABLE);
+            });
+            // Cancel
+            const cancelOrdersUpToThisSalt = new BigNumber(1);
+            const txReceipt = await erc721MakerBalanceThresholdWrapper.cancelOrdersUpToAsync(
+                cancelOrdersUpToThisSalt,
+                validSignedOrders[0].makerAddress,
+            );
+            // Assert validated addresses
+            const expectedValidatedAddresseses: string[] = [];
+            await assertValidatedAddressesLog(txReceipt, expectedValidatedAddresseses);
+            // Check that order was cancelled
+            _.each(validSignedOrders, async (signedOrder, salt: number) => {
+                const orderInfoAfterCancelling = await erc721MakerBalanceThresholdWrapper.getOrderInfoAsync(
+                    signedOrder,
+                );
+                const saltAsBigNumber = new BigNumber(salt);
+                if (saltAsBigNumber.lessThanOrEqualTo(cancelOrdersUpToThisSalt)) {
+                    return expect(orderInfoAfterCancelling.orderStatus).to.be.equal(OrderStatus.CANCELLED);
+                } else {
+                    return expect(orderInfoAfterCancelling.orderStatus).to.be.equal(OrderStatus.FILLABLE);
+                }
+            });
+        });
+        it('Should successfully batch cancel order if maker does not meet balance threshold', async () => {
+            // Create orders to cancel
+            const invalidSignedOrders = [
+                await invalidOrderFactory.newSignedOrderAsync({ salt: new BigNumber(0) }),
+                await invalidOrderFactory.newSignedOrderAsync({ salt: new BigNumber(1) }),
+                await invalidOrderFactory.newSignedOrderAsync({ salt: new BigNumber(2) }),
+            ];
+            // Verify orders are not cancelled
+            _.each(invalidSignedOrders, async signedOrder => {
+                const orderInfoBeforeCancelling = await erc721NonValidBalanceThresholdWrapper.getOrderInfoAsync(
+                    signedOrder,
+                );
+                return expect(orderInfoBeforeCancelling.orderStatus).to.be.equal(OrderStatus.FILLABLE);
+            });
+            // Cancel
+            const cancelOrdersUpToThisSalt = new BigNumber(1);
+            const txReceipt = await erc721NonValidBalanceThresholdWrapper.cancelOrdersUpToAsync(
+                cancelOrdersUpToThisSalt,
+                invalidAddress,
+            );
+            // Assert validated addresses
+            const expectedValidatedAddresseses: string[] = [];
+            await assertValidatedAddressesLog(txReceipt, expectedValidatedAddresseses);
+            // Check that order was cancelled
+            _.each(invalidSignedOrders, async (signedOrder, salt: number) => {
+                const orderInfoAfterCancelling = await erc721NonValidBalanceThresholdWrapper.getOrderInfoAsync(
+                    signedOrder,
+                );
+                const saltAsBigNumber = new BigNumber(salt);
+                if (saltAsBigNumber.lessThanOrEqualTo(cancelOrdersUpToThisSalt)) {
+                    return expect(orderInfoAfterCancelling.orderStatus).to.be.equal(OrderStatus.CANCELLED);
+                } else {
+                    return expect(orderInfoAfterCancelling.orderStatus).to.be.equal(OrderStatus.FILLABLE);
+                }
+            });
+        });
+    });
+});
+// tslint:disable:max-file-line-count
+// tslint:enable:no-unnecessary-type-assertion
diff --git a/contracts/extensions/test/extensions/forwarder.ts b/contracts/extensions/test/extensions/forwarder.ts
index 4027f493d..69939ed04 100644
--- a/contracts/extensions/test/extensions/forwarder.ts
+++ b/contracts/extensions/test/extensions/forwarder.ts
@@ -48,7 +48,6 @@ describe(ContractName.Forwarder, () => {
     let owner: string;
     let takerAddress: string;
     let feeRecipientAddress: string;
-    let otherAddress: string;
     let defaultMakerAssetAddress: string;
     let zrxAssetData: string;
     let wethAssetData: string;
@@ -78,7 +77,7 @@ describe(ContractName.Forwarder, () => {
     before(async () => {
         await blockchainLifecycle.startAsync();
         const accounts = await web3Wrapper.getAvailableAddressesAsync();
-        const usedAddresses = ([owner, makerAddress, takerAddress, feeRecipientAddress, otherAddress] = accounts);
+        const usedAddresses = ([owner, makerAddress, takerAddress, feeRecipientAddress] = accounts);
 
         const txHash = await web3Wrapper.sendTransactionAsync({ from: accounts[0], to: accounts[0], value: 0 });
         const transaction = await web3Wrapper.getTransactionByHashAsync(txHash);
diff --git a/contracts/extensions/test/extensions/order_matcher.ts b/contracts/extensions/test/extensions/order_matcher.ts
new file mode 100644
index 000000000..acb46ced4
--- /dev/null
+++ b/contracts/extensions/test/extensions/order_matcher.ts
@@ -0,0 +1,818 @@
+import {
+    artifacts as protocolArtifacts,
+    ERC20ProxyContract,
+    ERC20Wrapper,
+    ERC721ProxyContract,
+    ExchangeContract,
+    ExchangeFillEventArgs,
+    ExchangeWrapper,
+} from '@0x/contracts-protocol';
+import {
+    chaiSetup,
+    constants,
+    ERC20BalancesByOwner,
+    expectContractCreationFailedAsync,
+    expectTransactionFailedAsync,
+    LogDecoder,
+    OrderFactory,
+    provider,
+    sendTransactionResult,
+    txDefaults,
+    web3Wrapper,
+} from '@0x/contracts-test-utils';
+import { artifacts as tokenArtifacts, DummyERC20TokenContract, DummyERC721TokenContract } from '@0x/contracts-tokens';
+import { BlockchainLifecycle } from '@0x/dev-utils';
+import { assetDataUtils } from '@0x/order-utils';
+import { RevertReason } from '@0x/types';
+import { BigNumber } from '@0x/utils';
+import { Web3Wrapper } from '@0x/web3-wrapper';
+import * as chai from 'chai';
+import { LogWithDecodedArgs } from 'ethereum-types';
+import * as _ from 'lodash';
+
+import { OrderMatcherContract } from '../../generated-wrappers/order_matcher';
+import { artifacts } from '../../src/artifacts';
+
+const blockchainLifecycle = new BlockchainLifecycle(web3Wrapper);
+chaiSetup.configure();
+const expect = chai.expect;
+// tslint:disable:no-unnecessary-type-assertion
+describe('OrderMatcher', () => {
+    let makerAddressLeft: string;
+    let makerAddressRight: string;
+    let owner: string;
+    let takerAddress: string;
+    let feeRecipientAddressLeft: string;
+    let feeRecipientAddressRight: string;
+
+    let erc20TokenA: DummyERC20TokenContract;
+    let erc20TokenB: DummyERC20TokenContract;
+    let zrxToken: DummyERC20TokenContract;
+    let exchange: ExchangeContract;
+    let erc20Proxy: ERC20ProxyContract;
+    let erc721Proxy: ERC721ProxyContract;
+    let orderMatcher: OrderMatcherContract;
+
+    let erc20BalancesByOwner: ERC20BalancesByOwner;
+    let exchangeWrapper: ExchangeWrapper;
+    let erc20Wrapper: ERC20Wrapper;
+    let orderFactoryLeft: OrderFactory;
+    let orderFactoryRight: OrderFactory;
+
+    let leftMakerAssetData: string;
+    let leftTakerAssetData: string;
+    let defaultERC20MakerAssetAddress: string;
+    let defaultERC20TakerAssetAddress: string;
+
+    before(async () => {
+        await blockchainLifecycle.startAsync();
+    });
+    after(async () => {
+        await blockchainLifecycle.revertAsync();
+    });
+    before(async () => {
+        // Create accounts
+        const accounts = await web3Wrapper.getAvailableAddressesAsync();
+        // Hack(albrow): Both Prettier and TSLint insert a trailing comma below
+        // but that is invalid syntax as of TypeScript version >= 2.8. We don't
+        // have the right fine-grained configuration options in TSLint,
+        // Prettier, or TypeScript, to reconcile this, so we will just have to
+        // wait for them to sort it out. We disable TSLint and Prettier for
+        // this part of the code for now. This occurs several times in this
+        // file. See https://github.com/prettier/prettier/issues/4624.
+        // prettier-ignore
+        const usedAddresses = ([
+            owner,
+            makerAddressLeft,
+            makerAddressRight,
+            takerAddress,
+            feeRecipientAddressLeft,
+            // tslint:disable-next-line:trailing-comma
+            feeRecipientAddressRight
+        ] = _.slice(accounts, 0, 6));
+        // Create wrappers
+        erc20Wrapper = new ERC20Wrapper(provider, usedAddresses, owner);
+        // Deploy ERC20 token & ERC20 proxy
+        const numDummyErc20ToDeploy = 3;
+        [erc20TokenA, erc20TokenB, zrxToken] = await erc20Wrapper.deployDummyTokensAsync(
+            numDummyErc20ToDeploy,
+            constants.DUMMY_TOKEN_DECIMALS,
+        );
+        erc20Proxy = await erc20Wrapper.deployProxyAsync();
+        await erc20Wrapper.setBalancesAndAllowancesAsync();
+        // Deploy ERC721 proxy
+        erc721Proxy = await ERC721ProxyContract.deployFrom0xArtifactAsync(
+            protocolArtifacts.ERC721Proxy,
+            provider,
+            txDefaults,
+        );
+        // Depoy exchange
+        exchange = await ExchangeContract.deployFrom0xArtifactAsync(
+            protocolArtifacts.Exchange,
+            provider,
+            txDefaults,
+            assetDataUtils.encodeERC20AssetData(zrxToken.address),
+        );
+        exchangeWrapper = new ExchangeWrapper(exchange, provider);
+        await exchangeWrapper.registerAssetProxyAsync(erc20Proxy.address, owner);
+        await exchangeWrapper.registerAssetProxyAsync(erc721Proxy.address, owner);
+        // Authorize ERC20 trades by exchange
+        await web3Wrapper.awaitTransactionSuccessAsync(
+            await erc20Proxy.addAuthorizedAddress.sendTransactionAsync(exchange.address, {
+                from: owner,
+            }),
+            constants.AWAIT_TRANSACTION_MINED_MS,
+        );
+        // Deploy OrderMatcher
+        orderMatcher = await OrderMatcherContract.deployFrom0xArtifactAsync(
+            artifacts.OrderMatcher,
+            provider,
+            txDefaults,
+            exchange.address,
+        );
+        // Set default addresses
+        defaultERC20MakerAssetAddress = erc20TokenA.address;
+        defaultERC20TakerAssetAddress = erc20TokenB.address;
+        leftMakerAssetData = assetDataUtils.encodeERC20AssetData(defaultERC20MakerAssetAddress);
+        leftTakerAssetData = assetDataUtils.encodeERC20AssetData(defaultERC20TakerAssetAddress);
+        // Set OrderMatcher balances and allowances
+        await web3Wrapper.awaitTransactionSuccessAsync(
+            await erc20TokenA.setBalance.sendTransactionAsync(orderMatcher.address, constants.INITIAL_ERC20_BALANCE, {
+                from: owner,
+            }),
+            constants.AWAIT_TRANSACTION_MINED_MS,
+        );
+        await web3Wrapper.awaitTransactionSuccessAsync(
+            await erc20TokenB.setBalance.sendTransactionAsync(orderMatcher.address, constants.INITIAL_ERC20_BALANCE, {
+                from: owner,
+            }),
+            constants.AWAIT_TRANSACTION_MINED_MS,
+        );
+        await web3Wrapper.awaitTransactionSuccessAsync(
+            await orderMatcher.approveAssetProxy.sendTransactionAsync(
+                leftMakerAssetData,
+                constants.INITIAL_ERC20_ALLOWANCE,
+            ),
+            constants.AWAIT_TRANSACTION_MINED_MS,
+        );
+        await web3Wrapper.awaitTransactionSuccessAsync(
+            await orderMatcher.approveAssetProxy.sendTransactionAsync(
+                leftTakerAssetData,
+                constants.INITIAL_ERC20_ALLOWANCE,
+            ),
+            constants.AWAIT_TRANSACTION_MINED_MS,
+        );
+        // Create default order parameters
+        const defaultOrderParamsLeft = {
+            ...constants.STATIC_ORDER_PARAMS,
+            makerAddress: makerAddressLeft,
+            exchangeAddress: exchange.address,
+            makerAssetData: leftMakerAssetData,
+            takerAssetData: leftTakerAssetData,
+            feeRecipientAddress: feeRecipientAddressLeft,
+            makerFee: constants.ZERO_AMOUNT,
+            takerFee: constants.ZERO_AMOUNT,
+        };
+        const defaultOrderParamsRight = {
+            ...constants.STATIC_ORDER_PARAMS,
+            makerAddress: makerAddressRight,
+            exchangeAddress: exchange.address,
+            makerAssetData: leftTakerAssetData,
+            takerAssetData: leftMakerAssetData,
+            feeRecipientAddress: feeRecipientAddressRight,
+            makerFee: constants.ZERO_AMOUNT,
+            takerFee: constants.ZERO_AMOUNT,
+        };
+        const privateKeyLeft = constants.TESTRPC_PRIVATE_KEYS[accounts.indexOf(makerAddressLeft)];
+        orderFactoryLeft = new OrderFactory(privateKeyLeft, defaultOrderParamsLeft);
+        const privateKeyRight = constants.TESTRPC_PRIVATE_KEYS[accounts.indexOf(makerAddressRight)];
+        orderFactoryRight = new OrderFactory(privateKeyRight, defaultOrderParamsRight);
+    });
+    beforeEach(async () => {
+        await blockchainLifecycle.startAsync();
+    });
+    afterEach(async () => {
+        await blockchainLifecycle.revertAsync();
+    });
+    describe('constructor', () => {
+        it('should revert if assetProxy is unregistered', async () => {
+            const exchangeInstance = await ExchangeContract.deployFrom0xArtifactAsync(
+                protocolArtifacts.Exchange,
+                provider,
+                txDefaults,
+                constants.NULL_BYTES,
+            );
+            return expectContractCreationFailedAsync(
+                (OrderMatcherContract.deployFrom0xArtifactAsync(
+                    artifacts.OrderMatcher,
+                    provider,
+                    txDefaults,
+                    exchangeInstance.address,
+                ) as any) as sendTransactionResult,
+                RevertReason.UnregisteredAssetProxy,
+            );
+        });
+    });
+    describe('matchOrders', () => {
+        beforeEach(async () => {
+            erc20BalancesByOwner = await erc20Wrapper.getBalancesAsync();
+        });
+        it('should revert if not called by owner', async () => {
+            // Create orders to match
+            const signedOrderLeft = await orderFactoryLeft.newSignedOrderAsync({
+                makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(5), 18),
+                takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
+            });
+            const signedOrderRight = await orderFactoryRight.newSignedOrderAsync({
+                makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
+                takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(2), 18),
+            });
+            const data = exchange.matchOrders.getABIEncodedTransactionData(
+                signedOrderLeft,
+                signedOrderRight,
+                signedOrderLeft.signature,
+                signedOrderRight.signature,
+            );
+            await expectTransactionFailedAsync(
+                web3Wrapper.sendTransactionAsync({
+                    data,
+                    to: orderMatcher.address,
+                    from: takerAddress,
+                    gas: constants.MAX_MATCH_ORDERS_GAS,
+                }),
+                RevertReason.OnlyContractOwner,
+            );
+        });
+        it('should transfer the correct amounts when orders completely fill each other', async () => {
+            // Create orders to match
+            const signedOrderLeft = await orderFactoryLeft.newSignedOrderAsync({
+                makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(5), 18),
+                takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
+            });
+            const signedOrderRight = await orderFactoryRight.newSignedOrderAsync({
+                makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
+                takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(2), 18),
+            });
+            // Match signedOrderLeft with signedOrderRight
+            const expectedTransferAmounts = {
+                // Left Maker
+                amountSoldByLeftMaker: signedOrderLeft.makerAssetAmount,
+                amountBoughtByLeftMaker: signedOrderLeft.takerAssetAmount,
+                // Right Maker
+                amountSoldByRightMaker: signedOrderRight.makerAssetAmount,
+                amountBoughtByRightMaker: signedOrderRight.takerAssetAmount,
+                // Taker
+                leftMakerAssetSpreadAmount: signedOrderLeft.makerAssetAmount.minus(signedOrderRight.takerAssetAmount),
+            };
+            const initialLeftMakerAssetTakerBalance = await erc20TokenA.balanceOf.callAsync(orderMatcher.address);
+            const data = exchange.matchOrders.getABIEncodedTransactionData(
+                signedOrderLeft,
+                signedOrderRight,
+                signedOrderLeft.signature,
+                signedOrderRight.signature,
+            );
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await web3Wrapper.sendTransactionAsync({
+                    data,
+                    to: orderMatcher.address,
+                    from: owner,
+                    gas: constants.MAX_MATCH_ORDERS_GAS,
+                }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            const newLeftMakerAssetTakerBalance = await erc20TokenA.balanceOf.callAsync(orderMatcher.address);
+            const newErc20Balances = await erc20Wrapper.getBalancesAsync();
+            expect(newErc20Balances[makerAddressLeft][defaultERC20MakerAssetAddress]).to.be.bignumber.equal(
+                erc20BalancesByOwner[makerAddressLeft][defaultERC20MakerAssetAddress].minus(
+                    expectedTransferAmounts.amountSoldByLeftMaker,
+                ),
+            );
+            expect(newErc20Balances[makerAddressRight][defaultERC20TakerAssetAddress]).to.be.bignumber.equal(
+                erc20BalancesByOwner[makerAddressRight][defaultERC20TakerAssetAddress].minus(
+                    expectedTransferAmounts.amountSoldByRightMaker,
+                ),
+            );
+            expect(newErc20Balances[makerAddressLeft][defaultERC20TakerAssetAddress]).to.be.bignumber.equal(
+                erc20BalancesByOwner[makerAddressLeft][defaultERC20TakerAssetAddress].plus(
+                    expectedTransferAmounts.amountBoughtByLeftMaker,
+                ),
+            );
+            expect(newErc20Balances[makerAddressRight][defaultERC20MakerAssetAddress]).to.be.bignumber.equal(
+                erc20BalancesByOwner[makerAddressRight][defaultERC20MakerAssetAddress].plus(
+                    expectedTransferAmounts.amountBoughtByRightMaker,
+                ),
+            );
+            expect(newLeftMakerAssetTakerBalance).to.be.bignumber.equal(
+                initialLeftMakerAssetTakerBalance.plus(expectedTransferAmounts.leftMakerAssetSpreadAmount),
+            );
+        });
+        it('should transfer the correct amounts when orders completely fill each other and taker doesnt take a profit', async () => {
+            // Create orders to match
+            const signedOrderLeft = await orderFactoryLeft.newSignedOrderAsync({
+                makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(5), 18),
+                takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
+            });
+            const signedOrderRight = await orderFactoryRight.newSignedOrderAsync({
+                makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
+                takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(5), 18),
+            });
+            // Match signedOrderLeft with signedOrderRight
+            const expectedTransferAmounts = {
+                // Left Maker
+                amountSoldByLeftMaker: signedOrderLeft.makerAssetAmount,
+                amountBoughtByLeftMaker: signedOrderLeft.takerAssetAmount,
+                // Right Maker
+                amountSoldByRightMaker: signedOrderRight.makerAssetAmount,
+                amountBoughtByRightMaker: signedOrderRight.takerAssetAmount,
+            };
+            const initialLeftMakerAssetTakerBalance = await erc20TokenA.balanceOf.callAsync(orderMatcher.address);
+            const data = exchange.matchOrders.getABIEncodedTransactionData(
+                signedOrderLeft,
+                signedOrderRight,
+                signedOrderLeft.signature,
+                signedOrderRight.signature,
+            );
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await web3Wrapper.sendTransactionAsync({
+                    data,
+                    to: orderMatcher.address,
+                    from: owner,
+                    gas: constants.MAX_MATCH_ORDERS_GAS,
+                }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            const newLeftMakerAssetTakerBalance = await erc20TokenA.balanceOf.callAsync(orderMatcher.address);
+            const newErc20Balances = await erc20Wrapper.getBalancesAsync();
+            expect(newErc20Balances[makerAddressLeft][defaultERC20MakerAssetAddress]).to.be.bignumber.equal(
+                erc20BalancesByOwner[makerAddressLeft][defaultERC20MakerAssetAddress].minus(
+                    expectedTransferAmounts.amountSoldByLeftMaker,
+                ),
+            );
+            expect(newErc20Balances[makerAddressRight][defaultERC20TakerAssetAddress]).to.be.bignumber.equal(
+                erc20BalancesByOwner[makerAddressRight][defaultERC20TakerAssetAddress].minus(
+                    expectedTransferAmounts.amountSoldByRightMaker,
+                ),
+            );
+            expect(newErc20Balances[makerAddressLeft][defaultERC20TakerAssetAddress]).to.be.bignumber.equal(
+                erc20BalancesByOwner[makerAddressLeft][defaultERC20TakerAssetAddress].plus(
+                    expectedTransferAmounts.amountBoughtByLeftMaker,
+                ),
+            );
+            expect(newErc20Balances[makerAddressRight][defaultERC20MakerAssetAddress]).to.be.bignumber.equal(
+                erc20BalancesByOwner[makerAddressRight][defaultERC20MakerAssetAddress].plus(
+                    expectedTransferAmounts.amountBoughtByRightMaker,
+                ),
+            );
+            expect(newLeftMakerAssetTakerBalance).to.be.bignumber.equal(initialLeftMakerAssetTakerBalance);
+        });
+        it('should transfer the correct amounts when left order is completely filled and right order would be partially filled', async () => {
+            // Create orders to match
+            const signedOrderLeft = await orderFactoryLeft.newSignedOrderAsync({
+                makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(5), 18),
+                takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
+            });
+            const signedOrderRight = await orderFactoryRight.newSignedOrderAsync({
+                makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(20), 18),
+                takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(4), 18),
+            });
+            // Match signedOrderLeft with signedOrderRight
+            const expectedTransferAmounts = {
+                // Left Maker
+                amountSoldByLeftMaker: signedOrderLeft.makerAssetAmount,
+                amountBoughtByLeftMaker: signedOrderLeft.takerAssetAmount,
+                // Right Maker
+                amountSoldByRightMaker: signedOrderRight.makerAssetAmount,
+                amountBoughtByRightMaker: signedOrderRight.takerAssetAmount,
+                // Taker
+                leftMakerAssetSpreadAmount: signedOrderLeft.makerAssetAmount.minus(signedOrderRight.takerAssetAmount),
+                leftTakerAssetSpreadAmount: signedOrderRight.makerAssetAmount.minus(signedOrderLeft.takerAssetAmount),
+            };
+            const initialLeftMakerAssetTakerBalance = await erc20TokenA.balanceOf.callAsync(orderMatcher.address);
+            const initialLeftTakerAssetTakerBalance = await erc20TokenB.balanceOf.callAsync(orderMatcher.address);
+            // Match signedOrderLeft with signedOrderRight
+            const data = exchange.matchOrders.getABIEncodedTransactionData(
+                signedOrderLeft,
+                signedOrderRight,
+                signedOrderLeft.signature,
+                signedOrderRight.signature,
+            );
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await web3Wrapper.sendTransactionAsync({
+                    data,
+                    to: orderMatcher.address,
+                    from: owner,
+                    gas: constants.MAX_MATCH_ORDERS_GAS,
+                }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            const newLeftMakerAssetTakerBalance = await erc20TokenA.balanceOf.callAsync(orderMatcher.address);
+            const newLeftTakerAssetTakerBalance = await erc20TokenB.balanceOf.callAsync(orderMatcher.address);
+            const newErc20Balances = await erc20Wrapper.getBalancesAsync();
+            expect(newErc20Balances[makerAddressLeft][defaultERC20MakerAssetAddress]).to.be.bignumber.equal(
+                erc20BalancesByOwner[makerAddressLeft][defaultERC20MakerAssetAddress].minus(
+                    expectedTransferAmounts.amountSoldByLeftMaker,
+                ),
+            );
+            expect(newErc20Balances[makerAddressRight][defaultERC20TakerAssetAddress]).to.be.bignumber.equal(
+                erc20BalancesByOwner[makerAddressRight][defaultERC20TakerAssetAddress].minus(
+                    expectedTransferAmounts.amountSoldByRightMaker,
+                ),
+            );
+            expect(newErc20Balances[makerAddressLeft][defaultERC20TakerAssetAddress]).to.be.bignumber.equal(
+                erc20BalancesByOwner[makerAddressLeft][defaultERC20TakerAssetAddress].plus(
+                    expectedTransferAmounts.amountBoughtByLeftMaker,
+                ),
+            );
+            expect(newErc20Balances[makerAddressRight][defaultERC20MakerAssetAddress]).to.be.bignumber.equal(
+                erc20BalancesByOwner[makerAddressRight][defaultERC20MakerAssetAddress].plus(
+                    expectedTransferAmounts.amountBoughtByRightMaker,
+                ),
+            );
+            expect(newLeftMakerAssetTakerBalance).to.be.bignumber.equal(
+                initialLeftMakerAssetTakerBalance.plus(expectedTransferAmounts.leftMakerAssetSpreadAmount),
+            );
+            expect(newLeftTakerAssetTakerBalance).to.be.bignumber.equal(
+                initialLeftTakerAssetTakerBalance.plus(expectedTransferAmounts.leftTakerAssetSpreadAmount),
+            );
+        });
+        it('should not call fillOrder when rightOrder is completely filled after matchOrders call and orders were never partially filled', async () => {
+            // Create orders to match
+            const signedOrderLeft = await orderFactoryLeft.newSignedOrderAsync({
+                makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(5), 18),
+                takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
+            });
+            const signedOrderRight = await orderFactoryRight.newSignedOrderAsync({
+                makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
+                takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(2), 18),
+            });
+            const data = exchange.matchOrders.getABIEncodedTransactionData(
+                signedOrderLeft,
+                signedOrderRight,
+                signedOrderLeft.signature,
+                signedOrderRight.signature,
+            );
+            const logDecoder = new LogDecoder(web3Wrapper, { ...artifacts, ...tokenArtifacts, ...protocolArtifacts });
+            const txReceipt = await logDecoder.getTxWithDecodedLogsAsync(
+                await web3Wrapper.sendTransactionAsync({
+                    data,
+                    to: orderMatcher.address,
+                    from: owner,
+                    gas: constants.MAX_MATCH_ORDERS_GAS,
+                }),
+            );
+            const fillLogs = _.filter(
+                txReceipt.logs,
+                log => (log as LogWithDecodedArgs<ExchangeFillEventArgs>).event === 'Fill',
+            );
+            // Only 2 Fill logs should exist for `matchOrders` call. `fillOrder` should not have been called and should not have emitted a Fill event.
+            expect(fillLogs.length).to.be.equal(2);
+        });
+        it('should not call fillOrder when rightOrder is completely filled after matchOrders call and orders were initially partially filled', async () => {
+            // Create orders to match
+            const signedOrderLeft = await orderFactoryLeft.newSignedOrderAsync({
+                makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(5), 18),
+                takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
+            });
+            const signedOrderRight = await orderFactoryRight.newSignedOrderAsync({
+                makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
+                takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(2), 18),
+            });
+            await exchangeWrapper.fillOrderAsync(signedOrderLeft, takerAddress, {
+                takerAssetFillAmount: signedOrderLeft.takerAssetAmount.dividedToIntegerBy(5),
+            });
+            await exchangeWrapper.fillOrderAsync(signedOrderRight, takerAddress, {
+                takerAssetFillAmount: signedOrderRight.takerAssetAmount.dividedToIntegerBy(5),
+            });
+            const data = exchange.matchOrders.getABIEncodedTransactionData(
+                signedOrderLeft,
+                signedOrderRight,
+                signedOrderLeft.signature,
+                signedOrderRight.signature,
+            );
+            const logDecoder = new LogDecoder(web3Wrapper, { ...artifacts, ...tokenArtifacts, ...protocolArtifacts });
+            const txReceipt = await logDecoder.getTxWithDecodedLogsAsync(
+                await web3Wrapper.sendTransactionAsync({
+                    data,
+                    to: orderMatcher.address,
+                    from: owner,
+                    gas: constants.MAX_MATCH_ORDERS_GAS,
+                }),
+            );
+            const fillLogs = _.filter(
+                txReceipt.logs,
+                log => (log as LogWithDecodedArgs<ExchangeFillEventArgs>).event === 'Fill',
+            );
+            // Only 2 Fill logs should exist for `matchOrders` call. `fillOrder` should not have been called and should not have emitted a Fill event.
+            expect(fillLogs.length).to.be.equal(2);
+        });
+        it('should only take a spread in rightMakerAsset if entire leftMakerAssetSpread amount can be used to fill rightOrder after matchOrders call', async () => {
+            // Create orders to match
+            const signedOrderLeft = await orderFactoryLeft.newSignedOrderAsync({
+                makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
+                takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(0.9), 18),
+            });
+            const signedOrderRight = await orderFactoryRight.newSignedOrderAsync({
+                makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(100), 18),
+                takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(990), 18),
+            });
+            const initialLeftMakerAssetSpreadAmount = Web3Wrapper.toBaseUnitAmount(new BigNumber(1.09), 18);
+            const leftTakerAssetSpreadAmount = initialLeftMakerAssetSpreadAmount
+                .times(signedOrderRight.makerAssetAmount)
+                .dividedToIntegerBy(signedOrderRight.takerAssetAmount);
+            // Match signedOrderLeft with signedOrderRight
+            const expectedTransferAmounts = {
+                // Left Maker
+                amountSoldByLeftMaker: signedOrderLeft.makerAssetAmount,
+                amountBoughtByLeftMaker: signedOrderLeft.takerAssetAmount,
+                // Right Maker
+                amountSoldByRightMaker: signedOrderLeft.takerAssetAmount.plus(leftTakerAssetSpreadAmount),
+                amountBoughtByRightMaker: signedOrderLeft.makerAssetAmount,
+                // Taker
+                leftMakerAssetSpreadAmount: constants.ZERO_AMOUNT,
+                leftTakerAssetSpreadAmount,
+            };
+            const initialLeftMakerAssetTakerBalance = await erc20TokenA.balanceOf.callAsync(orderMatcher.address);
+            const initialLeftTakerAssetTakerBalance = await erc20TokenB.balanceOf.callAsync(orderMatcher.address);
+            // Match signedOrderLeft with signedOrderRight
+            const data = exchange.matchOrders.getABIEncodedTransactionData(
+                signedOrderLeft,
+                signedOrderRight,
+                signedOrderLeft.signature,
+                signedOrderRight.signature,
+            );
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await web3Wrapper.sendTransactionAsync({
+                    data,
+                    to: orderMatcher.address,
+                    from: owner,
+                    gas: constants.MAX_MATCH_ORDERS_GAS,
+                }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            const newLeftMakerAssetTakerBalance = await erc20TokenA.balanceOf.callAsync(orderMatcher.address);
+            const newLeftTakerAssetTakerBalance = await erc20TokenB.balanceOf.callAsync(orderMatcher.address);
+            const newErc20Balances = await erc20Wrapper.getBalancesAsync();
+            expect(newErc20Balances[makerAddressLeft][defaultERC20MakerAssetAddress]).to.be.bignumber.equal(
+                erc20BalancesByOwner[makerAddressLeft][defaultERC20MakerAssetAddress].minus(
+                    expectedTransferAmounts.amountSoldByLeftMaker,
+                ),
+            );
+            expect(newErc20Balances[makerAddressRight][defaultERC20TakerAssetAddress]).to.be.bignumber.equal(
+                erc20BalancesByOwner[makerAddressRight][defaultERC20TakerAssetAddress].minus(
+                    expectedTransferAmounts.amountSoldByRightMaker,
+                ),
+            );
+            expect(newErc20Balances[makerAddressLeft][defaultERC20TakerAssetAddress]).to.be.bignumber.equal(
+                erc20BalancesByOwner[makerAddressLeft][defaultERC20TakerAssetAddress].plus(
+                    expectedTransferAmounts.amountBoughtByLeftMaker,
+                ),
+            );
+            expect(newErc20Balances[makerAddressRight][defaultERC20MakerAssetAddress]).to.be.bignumber.equal(
+                erc20BalancesByOwner[makerAddressRight][defaultERC20MakerAssetAddress].plus(
+                    expectedTransferAmounts.amountBoughtByRightMaker,
+                ),
+            );
+            expect(newLeftMakerAssetTakerBalance).to.be.bignumber.equal(
+                initialLeftMakerAssetTakerBalance.plus(expectedTransferAmounts.leftMakerAssetSpreadAmount),
+            );
+            expect(newLeftTakerAssetTakerBalance).to.be.bignumber.equal(
+                initialLeftTakerAssetTakerBalance.plus(expectedTransferAmounts.leftTakerAssetSpreadAmount),
+            );
+        });
+        it("should succeed if rightOrder's makerAssetData and takerAssetData are not provided", async () => {
+            // Create orders to match
+            const signedOrderLeft = await orderFactoryLeft.newSignedOrderAsync({
+                makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(5), 18),
+                takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
+            });
+            const signedOrderRight = await orderFactoryRight.newSignedOrderAsync({
+                makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(20), 18),
+                takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(4), 18),
+            });
+            // Match signedOrderLeft with signedOrderRight
+            const expectedTransferAmounts = {
+                // Left Maker
+                amountSoldByLeftMaker: signedOrderLeft.makerAssetAmount,
+                amountBoughtByLeftMaker: signedOrderLeft.takerAssetAmount,
+                // Right Maker
+                amountSoldByRightMaker: signedOrderRight.makerAssetAmount,
+                amountBoughtByRightMaker: signedOrderRight.takerAssetAmount,
+                // Taker
+                leftMakerAssetSpreadAmount: signedOrderLeft.makerAssetAmount.minus(signedOrderRight.takerAssetAmount),
+                leftTakerAssetSpreadAmount: signedOrderRight.makerAssetAmount.minus(signedOrderLeft.takerAssetAmount),
+            };
+            const initialLeftMakerAssetTakerBalance = await erc20TokenA.balanceOf.callAsync(orderMatcher.address);
+            const initialLeftTakerAssetTakerBalance = await erc20TokenB.balanceOf.callAsync(orderMatcher.address);
+            // Match signedOrderLeft with signedOrderRight
+            signedOrderRight.makerAssetData = constants.NULL_BYTES;
+            signedOrderRight.takerAssetData = constants.NULL_BYTES;
+            const data = exchange.matchOrders.getABIEncodedTransactionData(
+                signedOrderLeft,
+                signedOrderRight,
+                signedOrderLeft.signature,
+                signedOrderRight.signature,
+            );
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await web3Wrapper.sendTransactionAsync({
+                    data,
+                    to: orderMatcher.address,
+                    from: owner,
+                    gas: constants.MAX_MATCH_ORDERS_GAS,
+                }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            const newLeftMakerAssetTakerBalance = await erc20TokenA.balanceOf.callAsync(orderMatcher.address);
+            const newLeftTakerAssetTakerBalance = await erc20TokenB.balanceOf.callAsync(orderMatcher.address);
+            const newErc20Balances = await erc20Wrapper.getBalancesAsync();
+            expect(newErc20Balances[makerAddressLeft][defaultERC20MakerAssetAddress]).to.be.bignumber.equal(
+                erc20BalancesByOwner[makerAddressLeft][defaultERC20MakerAssetAddress].minus(
+                    expectedTransferAmounts.amountSoldByLeftMaker,
+                ),
+            );
+            expect(newErc20Balances[makerAddressRight][defaultERC20TakerAssetAddress]).to.be.bignumber.equal(
+                erc20BalancesByOwner[makerAddressRight][defaultERC20TakerAssetAddress].minus(
+                    expectedTransferAmounts.amountSoldByRightMaker,
+                ),
+            );
+            expect(newErc20Balances[makerAddressLeft][defaultERC20TakerAssetAddress]).to.be.bignumber.equal(
+                erc20BalancesByOwner[makerAddressLeft][defaultERC20TakerAssetAddress].plus(
+                    expectedTransferAmounts.amountBoughtByLeftMaker,
+                ),
+            );
+            expect(newErc20Balances[makerAddressRight][defaultERC20MakerAssetAddress]).to.be.bignumber.equal(
+                erc20BalancesByOwner[makerAddressRight][defaultERC20MakerAssetAddress].plus(
+                    expectedTransferAmounts.amountBoughtByRightMaker,
+                ),
+            );
+            expect(newLeftMakerAssetTakerBalance).to.be.bignumber.equal(
+                initialLeftMakerAssetTakerBalance.plus(expectedTransferAmounts.leftMakerAssetSpreadAmount),
+            );
+            expect(newLeftTakerAssetTakerBalance).to.be.bignumber.equal(
+                initialLeftTakerAssetTakerBalance.plus(expectedTransferAmounts.leftTakerAssetSpreadAmount),
+            );
+        });
+        it('should revert with the correct reason if matchOrders call reverts', async () => {
+            // Create orders to match
+            const signedOrderLeft = await orderFactoryLeft.newSignedOrderAsync({
+                makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(5), 18),
+                takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
+            });
+            const signedOrderRight = await orderFactoryRight.newSignedOrderAsync({
+                makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
+                takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(5), 18),
+            });
+            signedOrderRight.signature = `0xff${signedOrderRight.signature.slice(4)}`;
+            const data = exchange.matchOrders.getABIEncodedTransactionData(
+                signedOrderLeft,
+                signedOrderRight,
+                signedOrderLeft.signature,
+                signedOrderRight.signature,
+            );
+            await expectTransactionFailedAsync(
+                web3Wrapper.sendTransactionAsync({
+                    data,
+                    to: orderMatcher.address,
+                    from: owner,
+                    gas: constants.MAX_MATCH_ORDERS_GAS,
+                }),
+                RevertReason.InvalidOrderSignature,
+            );
+        });
+        it('should revert with the correct reason if fillOrder call reverts', async () => {
+            // Create orders to match
+            const signedOrderLeft = await orderFactoryLeft.newSignedOrderAsync({
+                makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(5), 18),
+                takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
+            });
+            const signedOrderRight = await orderFactoryRight.newSignedOrderAsync({
+                makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(20), 18),
+                takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(4), 18),
+            });
+            // Matcher will not have enough allowance to fill rightOrder
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await orderMatcher.approveAssetProxy.sendTransactionAsync(leftMakerAssetData, constants.ZERO_AMOUNT, {
+                    from: owner,
+                }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            const data = exchange.matchOrders.getABIEncodedTransactionData(
+                signedOrderLeft,
+                signedOrderRight,
+                signedOrderLeft.signature,
+                signedOrderRight.signature,
+            );
+            await expectTransactionFailedAsync(
+                web3Wrapper.sendTransactionAsync({
+                    data,
+                    to: orderMatcher.address,
+                    from: owner,
+                    gas: constants.MAX_MATCH_ORDERS_GAS,
+                }),
+                RevertReason.TransferFailed,
+            );
+        });
+    });
+    describe('withdrawAsset', () => {
+        it('should allow owner to withdraw ERC20 tokens', async () => {
+            const erc20AWithdrawAmount = await erc20TokenA.balanceOf.callAsync(orderMatcher.address);
+            expect(erc20AWithdrawAmount).to.be.bignumber.gt(constants.ZERO_AMOUNT);
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await orderMatcher.withdrawAsset.sendTransactionAsync(leftMakerAssetData, erc20AWithdrawAmount, {
+                    from: owner,
+                }),
+            );
+            const newBalance = await erc20TokenA.balanceOf.callAsync(orderMatcher.address);
+            expect(newBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+        });
+        it('should allow owner to withdraw ERC721 tokens', async () => {
+            const erc721Token = await DummyERC721TokenContract.deployFrom0xArtifactAsync(
+                tokenArtifacts.DummyERC721Token,
+                provider,
+                txDefaults,
+                constants.DUMMY_TOKEN_NAME,
+                constants.DUMMY_TOKEN_SYMBOL,
+            );
+            const tokenId = new BigNumber(1);
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await erc721Token.mint.sendTransactionAsync(orderMatcher.address, tokenId, { from: owner }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            const assetData = assetDataUtils.encodeERC721AssetData(erc721Token.address, tokenId);
+            const withdrawAmount = new BigNumber(1);
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await orderMatcher.withdrawAsset.sendTransactionAsync(assetData, withdrawAmount, { from: owner }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            const erc721Owner = await erc721Token.ownerOf.callAsync(tokenId);
+            expect(erc721Owner).to.be.equal(owner);
+        });
+        it('should revert if not called by owner', async () => {
+            const erc20AWithdrawAmount = await erc20TokenA.balanceOf.callAsync(orderMatcher.address);
+            expect(erc20AWithdrawAmount).to.be.bignumber.gt(constants.ZERO_AMOUNT);
+            await expectTransactionFailedAsync(
+                orderMatcher.withdrawAsset.sendTransactionAsync(leftMakerAssetData, erc20AWithdrawAmount, {
+                    from: takerAddress,
+                }),
+                RevertReason.OnlyContractOwner,
+            );
+        });
+    });
+    describe('approveAssetProxy', () => {
+        it('should be able to set an allowance for ERC20 tokens', async () => {
+            const allowance = new BigNumber(55465465426546);
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await orderMatcher.approveAssetProxy.sendTransactionAsync(leftMakerAssetData, allowance, {
+                    from: owner,
+                }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            const newAllowance = await erc20TokenA.allowance.callAsync(orderMatcher.address, erc20Proxy.address);
+            expect(newAllowance).to.be.bignumber.equal(allowance);
+        });
+        it('should be able to approve an ERC721 token by passing in allowance = 1', async () => {
+            const erc721Token = await DummyERC721TokenContract.deployFrom0xArtifactAsync(
+                tokenArtifacts.DummyERC721Token,
+                provider,
+                txDefaults,
+                constants.DUMMY_TOKEN_NAME,
+                constants.DUMMY_TOKEN_SYMBOL,
+            );
+            const assetData = assetDataUtils.encodeERC721AssetData(erc721Token.address, constants.ZERO_AMOUNT);
+            const allowance = new BigNumber(1);
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await orderMatcher.approveAssetProxy.sendTransactionAsync(assetData, allowance, { from: owner }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            const isApproved = await erc721Token.isApprovedForAll.callAsync(orderMatcher.address, erc721Proxy.address);
+            expect(isApproved).to.be.equal(true);
+        });
+        it('should be able to approve an ERC721 token by passing in allowance > 1', async () => {
+            const erc721Token = await DummyERC721TokenContract.deployFrom0xArtifactAsync(
+                tokenArtifacts.DummyERC721Token,
+                provider,
+                txDefaults,
+                constants.DUMMY_TOKEN_NAME,
+                constants.DUMMY_TOKEN_SYMBOL,
+            );
+            const assetData = assetDataUtils.encodeERC721AssetData(erc721Token.address, constants.ZERO_AMOUNT);
+            const allowance = new BigNumber(2);
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await orderMatcher.approveAssetProxy.sendTransactionAsync(assetData, allowance, { from: owner }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            const isApproved = await erc721Token.isApprovedForAll.callAsync(orderMatcher.address, erc721Proxy.address);
+            expect(isApproved).to.be.equal(true);
+        });
+        it('should revert if not called by owner', async () => {
+            const approval = new BigNumber(1);
+            await expectTransactionFailedAsync(
+                orderMatcher.approveAssetProxy.sendTransactionAsync(leftMakerAssetData, approval, {
+                    from: takerAddress,
+                }),
+                RevertReason.OnlyContractOwner,
+            );
+        });
+    });
+});
+// tslint:disable:max-file-line-count
+// tslint:enable:no-unnecessary-type-assertion
diff --git a/contracts/protocol/test/exchange/order_validator.ts b/contracts/extensions/test/extensions/order_validator.ts
index 8f53426db..82a6b937f 100644
--- a/contracts/protocol/test/exchange/order_validator.ts
+++ b/contracts/extensions/test/extensions/order_validator.ts
@@ -1,4 +1,13 @@
 import {
+    artifacts as protocolArtifacts,
+    ERC20ProxyContract,
+    ERC20Wrapper,
+    ERC721ProxyContract,
+    ERC721Wrapper,
+    ExchangeContract,
+    ExchangeWrapper,
+} from '@0x/contracts-protocol';
+import {
     chaiSetup,
     constants,
     OrderFactory,
@@ -15,16 +24,8 @@ import { BigNumber } from '@0x/utils';
 import * as chai from 'chai';
 import * as _ from 'lodash';
 
-import {
-    artifacts,
-    ERC20ProxyContract,
-    ERC20Wrapper,
-    ERC721ProxyContract,
-    ERC721Wrapper,
-    ExchangeContract,
-    ExchangeWrapper,
-    OrderValidatorContract,
-} from '../../src';
+import { OrderValidatorContract } from '../../generated-wrappers/order_validator';
+import { artifacts } from '../../src/artifacts/index';
 
 chaiSetup.configure();
 const expect = chai.expect;
@@ -80,7 +81,7 @@ describe('OrderValidator', () => {
 
         const zrxAssetData = assetDataUtils.encodeERC20AssetData(zrxToken.address);
         exchange = await ExchangeContract.deployFrom0xArtifactAsync(
-            artifacts.Exchange,
+            protocolArtifacts.Exchange,
             provider,
             txDefaults,
             zrxAssetData,
diff --git a/contracts/extensions/test/utils/balance_threshold_wrapper.ts b/contracts/extensions/test/utils/balance_threshold_wrapper.ts
new file mode 100644
index 000000000..28a4ef011
--- /dev/null
+++ b/contracts/extensions/test/utils/balance_threshold_wrapper.ts
@@ -0,0 +1,283 @@
+import { artifacts as protocolArtifacts, ExchangeContract } from '@0x/contracts-protocol';
+import {
+    FillResults,
+    formatters,
+    LogDecoder,
+    OrderInfo,
+    orderUtils,
+    TransactionFactory,
+} from '@0x/contracts-test-utils';
+import { artifacts as tokensArtifacts } from '@0x/contracts-tokens';
+import { SignedOrder } from '@0x/types';
+import { BigNumber } from '@0x/utils';
+import { Web3Wrapper } from '@0x/web3-wrapper';
+import { Provider, TransactionReceiptWithDecodedLogs } from 'ethereum-types';
+import * as _ from 'lodash';
+
+import { BalanceThresholdFilterContract } from '../../generated-wrappers/balance_threshold_filter';
+import { artifacts } from '../../src/artifacts';
+
+export class BalanceThresholdWrapper {
+    private readonly _balanceThresholdFilter: BalanceThresholdFilterContract;
+    private readonly _signerTransactionFactory: TransactionFactory;
+    private readonly _exchange: ExchangeContract;
+    private readonly _web3Wrapper: Web3Wrapper;
+    private readonly _logDecoder: LogDecoder;
+    constructor(
+        balanceThresholdFilter: BalanceThresholdFilterContract,
+        exchangeContract: ExchangeContract,
+        signerTransactionFactory: TransactionFactory,
+        provider: Provider,
+    ) {
+        this._balanceThresholdFilter = balanceThresholdFilter;
+        this._exchange = exchangeContract;
+        this._signerTransactionFactory = signerTransactionFactory;
+        this._web3Wrapper = new Web3Wrapper(provider);
+        this._logDecoder = new LogDecoder(this._web3Wrapper, {
+            ...artifacts,
+            ...tokensArtifacts,
+            ...protocolArtifacts,
+        });
+    }
+    public async fillOrderAsync(
+        signedOrder: SignedOrder,
+        from: string,
+        opts: { takerAssetFillAmount?: BigNumber } = {},
+    ): Promise<TransactionReceiptWithDecodedLogs> {
+        const params = orderUtils.createFill(signedOrder, opts.takerAssetFillAmount);
+        const data = this._exchange.fillOrder.getABIEncodedTransactionData(
+            params.order,
+            params.takerAssetFillAmount,
+            params.signature,
+        );
+        const txReceipt = this._executeTransactionAsync(data, from);
+        return txReceipt;
+    }
+    public async fillOrKillOrderAsync(
+        signedOrder: SignedOrder,
+        from: string,
+        opts: { takerAssetFillAmount?: BigNumber } = {},
+    ): Promise<TransactionReceiptWithDecodedLogs> {
+        const params = orderUtils.createFill(signedOrder, opts.takerAssetFillAmount);
+        const data = this._exchange.fillOrKillOrder.getABIEncodedTransactionData(
+            params.order,
+            params.takerAssetFillAmount,
+            params.signature,
+        );
+        const txReceipt = this._executeTransactionAsync(data, from);
+        return txReceipt;
+    }
+    public async fillOrderNoThrowAsync(
+        signedOrder: SignedOrder,
+        from: string,
+        opts: { takerAssetFillAmount?: BigNumber; gas?: number } = {},
+    ): Promise<TransactionReceiptWithDecodedLogs> {
+        const params = orderUtils.createFill(signedOrder, opts.takerAssetFillAmount);
+        const data = this._exchange.fillOrderNoThrow.getABIEncodedTransactionData(
+            params.order,
+            params.takerAssetFillAmount,
+            params.signature,
+        );
+        const txReceipt = this._executeTransactionAsync(data, from, opts.gas);
+        return txReceipt;
+    }
+    public async batchFillOrdersAsync(
+        orders: SignedOrder[],
+        from: string,
+        opts: { takerAssetFillAmounts?: BigNumber[] } = {},
+    ): Promise<TransactionReceiptWithDecodedLogs> {
+        const params = formatters.createBatchFill(orders, opts.takerAssetFillAmounts);
+        const data = this._exchange.batchFillOrders.getABIEncodedTransactionData(
+            params.orders,
+            params.takerAssetFillAmounts,
+            params.signatures,
+        );
+        const txReceipt = this._executeTransactionAsync(data, from);
+        return txReceipt;
+    }
+    public async batchFillOrKillOrdersAsync(
+        orders: SignedOrder[],
+        from: string,
+        opts: { takerAssetFillAmounts?: BigNumber[] } = {},
+    ): Promise<TransactionReceiptWithDecodedLogs> {
+        const params = formatters.createBatchFill(orders, opts.takerAssetFillAmounts);
+        const data = this._exchange.batchFillOrKillOrders.getABIEncodedTransactionData(
+            params.orders,
+            params.takerAssetFillAmounts,
+            params.signatures,
+        );
+        const txReceipt = this._executeTransactionAsync(data, from);
+        return txReceipt;
+    }
+    public async batchFillOrdersNoThrowAsync(
+        orders: SignedOrder[],
+        from: string,
+        opts: { takerAssetFillAmounts?: BigNumber[]; gas?: number } = {},
+    ): Promise<TransactionReceiptWithDecodedLogs> {
+        const params = formatters.createBatchFill(orders, opts.takerAssetFillAmounts);
+        const data = this._exchange.batchFillOrKillOrders.getABIEncodedTransactionData(
+            params.orders,
+            params.takerAssetFillAmounts,
+            params.signatures,
+        );
+        const txReceipt = this._executeTransactionAsync(data, from, opts.gas);
+        return txReceipt;
+    }
+    public async marketSellOrdersAsync(
+        orders: SignedOrder[],
+        from: string,
+        opts: { takerAssetFillAmount: BigNumber },
+    ): Promise<TransactionReceiptWithDecodedLogs> {
+        const params = formatters.createMarketSellOrders(orders, opts.takerAssetFillAmount);
+        const data = this._exchange.marketSellOrders.getABIEncodedTransactionData(
+            params.orders,
+            params.takerAssetFillAmount,
+            params.signatures,
+        );
+        const txReceipt = this._executeTransactionAsync(data, from);
+        return txReceipt;
+    }
+    public async marketSellOrdersNoThrowAsync(
+        orders: SignedOrder[],
+        from: string,
+        opts: { takerAssetFillAmount: BigNumber; gas?: number },
+    ): Promise<TransactionReceiptWithDecodedLogs> {
+        const params = formatters.createMarketSellOrders(orders, opts.takerAssetFillAmount);
+        const data = this._exchange.marketSellOrdersNoThrow.getABIEncodedTransactionData(
+            params.orders,
+            params.takerAssetFillAmount,
+            params.signatures,
+        );
+        const txReceipt = this._executeTransactionAsync(data, from, opts.gas);
+        return txReceipt;
+    }
+    public async marketBuyOrdersAsync(
+        orders: SignedOrder[],
+        from: string,
+        opts: { makerAssetFillAmount: BigNumber },
+    ): Promise<TransactionReceiptWithDecodedLogs> {
+        const params = formatters.createMarketBuyOrders(orders, opts.makerAssetFillAmount);
+        const data = this._exchange.marketBuyOrders.getABIEncodedTransactionData(
+            params.orders,
+            params.makerAssetFillAmount,
+            params.signatures,
+        );
+        const txReceipt = this._executeTransactionAsync(data, from);
+        return txReceipt;
+    }
+    public async marketBuyOrdersNoThrowAsync(
+        orders: SignedOrder[],
+        from: string,
+        opts: { makerAssetFillAmount: BigNumber; gas?: number },
+    ): Promise<TransactionReceiptWithDecodedLogs> {
+        const params = formatters.createMarketBuyOrders(orders, opts.makerAssetFillAmount);
+        const data = this._exchange.marketBuyOrdersNoThrow.getABIEncodedTransactionData(
+            params.orders,
+            params.makerAssetFillAmount,
+            params.signatures,
+        );
+        const txReceipt = this._executeTransactionAsync(data, from, opts.gas);
+        return txReceipt;
+    }
+    public async cancelOrderAsync(signedOrder: SignedOrder, from: string): Promise<TransactionReceiptWithDecodedLogs> {
+        const params = orderUtils.createCancel(signedOrder);
+        const data = this._exchange.cancelOrder.getABIEncodedTransactionData(params.order);
+        const txReceipt = this._executeTransactionAsync(data, from);
+        return txReceipt;
+    }
+    public async batchCancelOrdersAsync(
+        orders: SignedOrder[],
+        from: string,
+    ): Promise<TransactionReceiptWithDecodedLogs> {
+        const params = formatters.createBatchCancel(orders);
+        const data = this._exchange.batchCancelOrders.getABIEncodedTransactionData(params.orders);
+        const txReceipt = this._executeTransactionAsync(data, from);
+        return txReceipt;
+    }
+    public async cancelOrdersUpToAsync(salt: BigNumber, from: string): Promise<TransactionReceiptWithDecodedLogs> {
+        const data = this._exchange.cancelOrdersUpTo.getABIEncodedTransactionData(salt);
+        const txReceipt = this._executeTransactionAsync(data, from);
+        return txReceipt;
+    }
+    public async getTakerAssetFilledAmountAsync(orderHashHex: string): Promise<BigNumber> {
+        const filledAmount = await this._exchange.filled.callAsync(orderHashHex);
+        return filledAmount;
+    }
+    public async isCancelledAsync(orderHashHex: string): Promise<boolean> {
+        const isCancelled = await this._exchange.cancelled.callAsync(orderHashHex);
+        return isCancelled;
+    }
+    public async getOrderEpochAsync(makerAddress: string, senderAddress: string): Promise<BigNumber> {
+        const orderEpoch = await this._exchange.orderEpoch.callAsync(makerAddress, senderAddress);
+        return orderEpoch;
+    }
+    public async getOrderInfoAsync(signedOrder: SignedOrder): Promise<OrderInfo> {
+        const orderInfo = await this._exchange.getOrderInfo.callAsync(signedOrder);
+        return orderInfo;
+    }
+    public async getOrdersInfoAsync(signedOrders: SignedOrder[]): Promise<OrderInfo[]> {
+        const ordersInfo = (await this._exchange.getOrdersInfo.callAsync(signedOrders)) as OrderInfo[];
+        return ordersInfo;
+    }
+    public async matchOrdersAsync(
+        signedOrderLeft: SignedOrder,
+        signedOrderRight: SignedOrder,
+        from: string,
+    ): Promise<TransactionReceiptWithDecodedLogs> {
+        const params = orderUtils.createMatchOrders(signedOrderLeft, signedOrderRight);
+        const data = await this._exchange.matchOrders.getABIEncodedTransactionData(
+            params.left,
+            params.right,
+            params.leftSignature,
+            params.rightSignature,
+        );
+        const txReceipt = this._executeTransactionAsync(data, from);
+        return txReceipt;
+    }
+    public async getFillOrderResultsAsync(
+        signedOrder: SignedOrder,
+        from: string,
+        opts: { takerAssetFillAmount?: BigNumber } = {},
+    ): Promise<FillResults> {
+        const params = orderUtils.createFill(signedOrder, opts.takerAssetFillAmount);
+        const fillResults = await this._exchange.fillOrder.callAsync(
+            params.order,
+            params.takerAssetFillAmount,
+            params.signature,
+            { from },
+        );
+        return fillResults;
+    }
+    public abiEncodeFillOrder(signedOrder: SignedOrder, opts: { takerAssetFillAmount?: BigNumber } = {}): string {
+        const params = orderUtils.createFill(signedOrder, opts.takerAssetFillAmount);
+        const data = this._exchange.fillOrder.getABIEncodedTransactionData(
+            params.order,
+            params.takerAssetFillAmount,
+            params.signature,
+        );
+        return data;
+    }
+    public getBalanceThresholdAddress(): string {
+        return this._balanceThresholdFilter.address;
+    }
+    public getExchangeAddress(): string {
+        return this._exchange.address;
+    }
+    private async _executeTransactionAsync(
+        abiEncodedExchangeTxData: string,
+        from: string,
+        gas?: number,
+    ): Promise<TransactionReceiptWithDecodedLogs> {
+        const signedExchangeTx = this._signerTransactionFactory.newSignedTransaction(abiEncodedExchangeTxData);
+        const txOpts = _.isUndefined(gas) ? { from } : { from, gas };
+        const txHash = await this._balanceThresholdFilter.executeTransaction.sendTransactionAsync(
+            signedExchangeTx.salt,
+            signedExchangeTx.signerAddress,
+            signedExchangeTx.data,
+            signedExchangeTx.signature,
+            txOpts,
+        );
+        const txReceipt = await this._logDecoder.getTxWithDecodedLogsAsync(txHash);
+        return txReceipt;
+    }
+}
diff --git a/contracts/extensions/tsconfig.json b/contracts/extensions/tsconfig.json
index a4ce1e002..ed9b4fbe1 100644
--- a/contracts/extensions/tsconfig.json
+++ b/contracts/extensions/tsconfig.json
@@ -6,6 +6,12 @@
         "resolveJsonModule": true
     },
     "include": ["./src/**/*", "./test/**/*", "./generated-wrappers/**/*"],
-    "files": ["./generated-artifacts/DutchAuction.json", "./generated-artifacts/Forwarder.json"],
+    "files": [
+        "./generated-artifacts/BalanceThresholdFilter.json",
+        "./generated-artifacts/DutchAuction.json",
+        "./generated-artifacts/Forwarder.json",
+        "./generated-artifacts/OrderMatcher.json",
+        "./generated-artifacts/OrderValidator.json"
+    ],
     "exclude": ["./deploy/solc/solc_bin"]
 }
diff --git a/contracts/interfaces/contracts/protocol/AssetProxy/IAssetData.sol b/contracts/interfaces/contracts/protocol/AssetProxy/IAssetData.sol
index e2da68919..a130e615f 100644
--- a/contracts/interfaces/contracts/protocol/AssetProxy/IAssetData.sol
+++ b/contracts/interfaces/contracts/protocol/AssetProxy/IAssetData.sol
@@ -17,7 +17,7 @@
 */
 
 // solhint-disable
-pragma solidity 0.4.24;
+pragma solidity ^0.4.24;
 pragma experimental ABIEncoderV2;
 
 
diff --git a/contracts/interfaces/contracts/protocol/AssetProxy/IAssetProxy.sol b/contracts/interfaces/contracts/protocol/AssetProxy/IAssetProxy.sol
index b25d2d75a..706412dd0 100644
--- a/contracts/interfaces/contracts/protocol/AssetProxy/IAssetProxy.sol
+++ b/contracts/interfaces/contracts/protocol/AssetProxy/IAssetProxy.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity 0.4.24;
+pragma solidity ^0.4.24;
 
 import "./IAuthorizable.sol";
 
diff --git a/contracts/interfaces/contracts/protocol/AssetProxy/IAuthorizable.sol b/contracts/interfaces/contracts/protocol/AssetProxy/IAuthorizable.sol
index 96ee05dee..202173998 100644
--- a/contracts/interfaces/contracts/protocol/AssetProxy/IAuthorizable.sol
+++ b/contracts/interfaces/contracts/protocol/AssetProxy/IAuthorizable.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity 0.4.24;
+pragma solidity ^0.4.24;
 
 import "@0x/contracts-utils/contracts/utils/Ownable/IOwnable.sol";
 
diff --git a/contracts/interfaces/contracts/protocol/Exchange/IAssetProxyDispatcher.sol b/contracts/interfaces/contracts/protocol/Exchange/IAssetProxyDispatcher.sol
index 8db8d6f6c..b73881c07 100644
--- a/contracts/interfaces/contracts/protocol/Exchange/IAssetProxyDispatcher.sol
+++ b/contracts/interfaces/contracts/protocol/Exchange/IAssetProxyDispatcher.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity 0.4.24;
+pragma solidity ^0.4.24;
 
 
 contract IAssetProxyDispatcher {
diff --git a/contracts/interfaces/contracts/protocol/Exchange/IExchange.sol b/contracts/interfaces/contracts/protocol/Exchange/IExchange.sol
index b92abba04..866e4c194 100644
--- a/contracts/interfaces/contracts/protocol/Exchange/IExchange.sol
+++ b/contracts/interfaces/contracts/protocol/Exchange/IExchange.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity 0.4.24;
+pragma solidity ^0.4.24;
 pragma experimental ABIEncoderV2;
 
 import "./IExchangeCore.sol";
diff --git a/contracts/interfaces/contracts/protocol/Exchange/IExchangeCore.sol b/contracts/interfaces/contracts/protocol/Exchange/IExchangeCore.sol
index 0da73529c..ab4a62408 100644
--- a/contracts/interfaces/contracts/protocol/Exchange/IExchangeCore.sol
+++ b/contracts/interfaces/contracts/protocol/Exchange/IExchangeCore.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity 0.4.24;
+pragma solidity ^0.4.24;
 pragma experimental ABIEncoderV2;
 
 import "@0x/contracts-libs/contracts/libs/LibOrder.sol";
diff --git a/contracts/interfaces/contracts/protocol/Exchange/IMatchOrders.sol b/contracts/interfaces/contracts/protocol/Exchange/IMatchOrders.sol
index b88e158c3..5df46ea80 100644
--- a/contracts/interfaces/contracts/protocol/Exchange/IMatchOrders.sol
+++ b/contracts/interfaces/contracts/protocol/Exchange/IMatchOrders.sol
@@ -15,7 +15,7 @@
   limitations under the License.
 
 */
-pragma solidity 0.4.24;
+pragma solidity ^0.4.24;
 pragma experimental ABIEncoderV2;
 
 import "@0x/contracts-libs/contracts/libs/LibOrder.sol";
diff --git a/contracts/interfaces/contracts/protocol/Exchange/ISignatureValidator.sol b/contracts/interfaces/contracts/protocol/Exchange/ISignatureValidator.sol
index 1fd0eccf0..c5a4a57e1 100644
--- a/contracts/interfaces/contracts/protocol/Exchange/ISignatureValidator.sol
+++ b/contracts/interfaces/contracts/protocol/Exchange/ISignatureValidator.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity 0.4.24;
+pragma solidity ^0.4.24;
 
 
 contract ISignatureValidator {
diff --git a/contracts/interfaces/contracts/protocol/Exchange/ITransactions.sol b/contracts/interfaces/contracts/protocol/Exchange/ITransactions.sol
index 4446c55ce..aaaee389f 100644
--- a/contracts/interfaces/contracts/protocol/Exchange/ITransactions.sol
+++ b/contracts/interfaces/contracts/protocol/Exchange/ITransactions.sol
@@ -15,7 +15,7 @@
   limitations under the License.
 
 */
-pragma solidity 0.4.24;
+pragma solidity ^0.4.24;
 
 
 contract ITransactions {
diff --git a/contracts/interfaces/contracts/protocol/Exchange/IValidator.sol b/contracts/interfaces/contracts/protocol/Exchange/IValidator.sol
index 2dd69100c..d214e54dd 100644
--- a/contracts/interfaces/contracts/protocol/Exchange/IValidator.sol
+++ b/contracts/interfaces/contracts/protocol/Exchange/IValidator.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity 0.4.24;
+pragma solidity ^0.4.24;
 
 
 contract IValidator {
diff --git a/contracts/interfaces/contracts/protocol/Exchange/IWallet.sol b/contracts/interfaces/contracts/protocol/Exchange/IWallet.sol
index c97161ca6..c2db4a5b1 100644
--- a/contracts/interfaces/contracts/protocol/Exchange/IWallet.sol
+++ b/contracts/interfaces/contracts/protocol/Exchange/IWallet.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity 0.4.24;
+pragma solidity ^0.4.24;
 
 
 contract IWallet {
diff --git a/contracts/interfaces/contracts/protocol/Exchange/IWrapperFunctions.sol b/contracts/interfaces/contracts/protocol/Exchange/IWrapperFunctions.sol
index 833bb7e88..0eeaa874b 100644
--- a/contracts/interfaces/contracts/protocol/Exchange/IWrapperFunctions.sol
+++ b/contracts/interfaces/contracts/protocol/Exchange/IWrapperFunctions.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity 0.4.24;
+pragma solidity ^0.4.24;
 pragma experimental ABIEncoderV2;
 
 import "@0x/contracts-libs/contracts/libs/LibOrder.sol";
diff --git a/contracts/interfaces/package.json b/contracts/interfaces/package.json
index 4d3e4b7f9..15385a154 100644
--- a/contracts/interfaces/package.json
+++ b/contracts/interfaces/package.json
@@ -10,7 +10,8 @@
         "build": "yarn pre_build && tsc -b",
         "build:ci": "yarn build",
         "pre_build": "run-s compile generate_contract_wrappers",
-        "compile": "sol-compiler --contracts-dir contracts",
+        "compile": "sol-compiler",
+        "watch": "sol-compiler -w",
         "clean": "shx rm -rf lib generated-artifacts generated-wrappers",
         "generate_contract_wrappers": "abi-gen --abis  ${npm_package_config_abis} --template ../../node_modules/@0x/abi-gen-templates/contract.handlebars --partials '../../node_modules/@0x/abi-gen-templates/partials/**/*.handlebars' --output generated-wrappers --backend ethers",
         "lint": "tslint --format stylish --project . --exclude ./generated-wrappers/**/* --exclude ./generated-artifacts/**/* --exclude **/lib/**/* && yarn lint-contracts",
diff --git a/contracts/libs/compiler.json b/contracts/libs/compiler.json
index cf7c52a73..349d3063b 100644
--- a/contracts/libs/compiler.json
+++ b/contracts/libs/compiler.json
@@ -18,5 +18,14 @@
             }
         }
     },
-    "contracts": ["TestLibs", "LibOrder", "LibMath", "LibFillResults", "LibAbiEncoder", "LibEIP712"]
+    "contracts": [
+        "TestLibs",
+        "LibOrder",
+        "LibMath",
+        "LibFillResults",
+        "LibAbiEncoder",
+        "LibEIP712",
+        "LibAssetProxyErrors",
+        "LibConstants"
+    ]
 }
diff --git a/contracts/libs/contracts/libs/LibAbiEncoder.sol b/contracts/libs/contracts/libs/LibAbiEncoder.sol
index 4aad37709..5422bfeec 100644
--- a/contracts/libs/contracts/libs/LibAbiEncoder.sol
+++ b/contracts/libs/contracts/libs/LibAbiEncoder.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity 0.4.24;
+pragma solidity ^0.4.24;
 pragma experimental ABIEncoderV2;
 
 import "./LibOrder.sol";
diff --git a/contracts/libs/contracts/libs/LibAddressArray.sol b/contracts/libs/contracts/libs/LibAddressArray.sol
new file mode 100644
index 000000000..997ce85fa
--- /dev/null
+++ b/contracts/libs/contracts/libs/LibAddressArray.sol
@@ -0,0 +1,84 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+
+import "@0x/contracts-utils/contracts/utils/LibBytes/LibBytes.sol";
+
+
+library LibAddressArray {
+
+    /// @dev Append a new address to an array of addresses.
+    ///      The `addressArray` may need to be reallocated to make space
+    ///      for the new address. Because of this we return the resulting
+    ///      memory location of `addressArray`.
+    /// @param addressToAppend  Address to append.
+    /// @return Array of addresses: [... addressArray, addressToAppend]
+    function append(address[] memory addressArray, address addressToAppend) 
+        internal pure
+        returns (address[])
+    {
+        // Get stats on address array and free memory
+        uint256 freeMemPtr = 0;
+        uint256 addressArrayBeginPtr = 0;
+        uint256 addressArrayEndPtr = 0;
+        uint256 addressArrayLength = addressArray.length;
+        uint256 addressArrayMemSizeInBytes = 32 + (32 * addressArrayLength);
+        assembly {
+            freeMemPtr := mload(0x40)
+            addressArrayBeginPtr := addressArray
+            addressArrayEndPtr := add(addressArray, addressArrayMemSizeInBytes)
+        }
+
+        // Cases for `freeMemPtr`:
+        //  `freeMemPtr` == `addressArrayEndPtr`: Nothing occupies memory after `addressArray`
+        //  `freeMemPtr` > `addressArrayEndPtr`: Some value occupies memory after `addressArray`
+        //  `freeMemPtr` < `addressArrayEndPtr`: Memory has not been managed properly.
+        require(
+            freeMemPtr >= addressArrayEndPtr,
+            "INVALID_FREE_MEMORY_PTR"
+        );
+
+        // If free memory begins at the end of `addressArray`
+        // then we can append `addressToAppend` directly.
+        // Otherwise, we must copy the array to free memory
+        // before appending new values to it.
+        if (freeMemPtr > addressArrayEndPtr) {
+            LibBytes.memCopy(freeMemPtr, addressArrayBeginPtr, addressArrayMemSizeInBytes);
+            assembly {
+                addressArray := freeMemPtr
+                addressArrayBeginPtr := addressArray
+            }
+        }
+
+        // Append `addressToAppend`
+        addressArrayLength += 1;
+        addressArrayMemSizeInBytes += 32;
+        addressArrayEndPtr = addressArrayBeginPtr + addressArrayMemSizeInBytes;
+        freeMemPtr = addressArrayEndPtr;
+        assembly {
+            // Store new array length
+            mstore(addressArray, addressArrayLength)
+
+            // Update `freeMemPtr`
+            mstore(0x40, freeMemPtr)
+        }
+        addressArray[addressArrayLength - 1] = addressToAppend;
+        return addressArray;
+    }
+}
diff --git a/contracts/libs/contracts/libs/LibAssetProxyErrors.sol b/contracts/libs/contracts/libs/LibAssetProxyErrors.sol
index 1d9a70cc1..96c48b5e3 100644
--- a/contracts/libs/contracts/libs/LibAssetProxyErrors.sol
+++ b/contracts/libs/contracts/libs/LibAssetProxyErrors.sol
@@ -17,7 +17,7 @@
 */
 
 // solhint-disable
-pragma solidity 0.4.24;
+pragma solidity ^0.4.24;
 
 
 /// @dev This contract documents the revert reasons used in the AssetProxy contracts.
diff --git a/contracts/libs/contracts/libs/LibConstants.sol b/contracts/libs/contracts/libs/LibConstants.sol
index 8d2732cd3..3efa3e1b3 100644
--- a/contracts/libs/contracts/libs/LibConstants.sol
+++ b/contracts/libs/contracts/libs/LibConstants.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity 0.4.24;
+pragma solidity ^0.4.24;
 
 
 // solhint-disable max-line-length
diff --git a/contracts/libs/contracts/libs/LibEIP712.sol b/contracts/libs/contracts/libs/LibEIP712.sol
index 203edc1fd..3a85ab3c0 100644
--- a/contracts/libs/contracts/libs/LibEIP712.sol
+++ b/contracts/libs/contracts/libs/LibEIP712.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity 0.4.24;
+pragma solidity ^0.4.24;
 
 
 contract LibEIP712 {
diff --git a/contracts/libs/contracts/libs/LibExchangeErrors.sol b/contracts/libs/contracts/libs/LibExchangeErrors.sol
index a0f75bc06..a160242c9 100644
--- a/contracts/libs/contracts/libs/LibExchangeErrors.sol
+++ b/contracts/libs/contracts/libs/LibExchangeErrors.sol
@@ -17,7 +17,7 @@
 */
 
 // solhint-disable
-pragma solidity 0.4.24;
+pragma solidity ^0.4.24;
 
 
 /// @dev This contract documents the revert reasons used in the Exchange contract.
diff --git a/contracts/libs/contracts/libs/LibExchangeSelectors.sol b/contracts/libs/contracts/libs/LibExchangeSelectors.sol
new file mode 100644
index 000000000..71640c609
--- /dev/null
+++ b/contracts/libs/contracts/libs/LibExchangeSelectors.sol
@@ -0,0 +1,152 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+
+
+contract LibExchangeSelectors {
+
+    // solhint-disable max-line-length
+    // allowedValidators
+    bytes4 constant public ALLOWED_VALIDATORS_SELECTOR = 0x7b8e3514;
+    bytes4 constant public ALLOWED_VALIDATORS_SELECTOR_GENERATOR = bytes4(keccak256("allowedValidators(address,address)"));
+
+    // assetProxies
+    bytes4 constant public ASSET_PROXIES_SELECTOR = 0x3fd3c997;
+    bytes4 constant public ASSET_PROXIES_SELECTOR_GENERATOR = bytes4(keccak256("assetProxies(bytes4)"));
+
+    // batchCancelOrders
+    bytes4 constant public BATCH_CANCEL_ORDERS_SELECTOR = 0x4ac14782;
+    bytes4 constant public BATCH_CANCEL_ORDERS_SELECTOR_GENERATOR = bytes4(keccak256("batchCancelOrders((address,address,address,address,uint256,uint256,uint256,uint256,uint256,uint256,bytes,bytes)[])"));
+
+    // batchFillOrKillOrders
+    bytes4 constant public BATCH_FILL_OR_KILL_ORDERS_SELECTOR = 0x4d0ae546;
+    bytes4 constant public BATCH_FILL_OR_KILL_ORDERS_SELECTOR_GENERATOR = bytes4(keccak256("batchFillOrKillOrders((address,address,address,address,uint256,uint256,uint256,uint256,uint256,uint256,bytes,bytes)[],uint256[],bytes[])"));
+
+    // batchFillOrders
+    bytes4 constant public BATCH_FILL_ORDERS_SELECTOR = 0x297bb70b;
+    bytes4 constant public BATCH_FILL_ORDERS_SELECTOR_GENERATOR = bytes4(keccak256("batchFillOrders((address,address,address,address,uint256,uint256,uint256,uint256,uint256,uint256,bytes,bytes)[],uint256[],bytes[])"));
+
+    // batchFillOrdersNoThrow
+    bytes4 constant public BATCH_FILL_ORDERS_NO_THROW_SELECTOR = 0x50dde190;
+    bytes4 constant public BATCH_FILL_ORDERS_NO_THROW_SELECTOR_GENERATOR = bytes4(keccak256("batchFillOrdersNoThrow((address,address,address,address,uint256,uint256,uint256,uint256,uint256,uint256,bytes,bytes)[],uint256[],bytes[])"));
+
+    // cancelOrder
+    bytes4 constant public CANCEL_ORDER_SELECTOR = 0xd46b02c3;
+    bytes4 constant public CANCEL_ORDER_SELECTOR_GENERATOR = bytes4(keccak256("cancelOrder((address,address,address,address,uint256,uint256,uint256,uint256,uint256,uint256,bytes,bytes))"));
+
+    // cancelOrdersUpTo
+    bytes4 constant public CANCEL_ORDERS_UP_TO_SELECTOR = 0x4f9559b1;
+    bytes4 constant public CANCEL_ORDERS_UP_TO_SELECTOR_GENERATOR = bytes4(keccak256("cancelOrdersUpTo(uint256)"));
+
+    // cancelled
+    bytes4 constant public CANCELLED_SELECTOR = 0x2ac12622;
+    bytes4 constant public CANCELLED_SELECTOR_GENERATOR = bytes4(keccak256("cancelled(bytes32)"));
+
+    // currentContextAddress
+    bytes4 constant public CURRENT_CONTEXT_ADDRESS_SELECTOR = 0xeea086ba;
+    bytes4 constant public CURRENT_CONTEXT_ADDRESS_SELECTOR_GENERATOR = bytes4(keccak256("currentContextAddress()"));
+
+    // executeTransaction
+    bytes4 constant public EXECUTE_TRANSACTION_SELECTOR = 0xbfc8bfce;
+    bytes4 constant public EXECUTE_TRANSACTION_SELECTOR_GENERATOR = bytes4(keccak256("executeTransaction(uint256,address,bytes,bytes)"));
+
+    // fillOrKillOrder
+    bytes4 constant public FILL_OR_KILL_ORDER_SELECTOR = 0x64a3bc15;
+    bytes4 constant public FILL_OR_KILL_ORDER_SELECTOR_GENERATOR = bytes4(keccak256("fillOrKillOrder((address,address,address,address,uint256,uint256,uint256,uint256,uint256,uint256,bytes,bytes),uint256,bytes)"));
+
+    // fillOrder
+    bytes4 constant public FILL_ORDER_SELECTOR = 0xb4be83d5;
+    bytes4 constant public FILL_ORDER_SELECTOR_GENERATOR = bytes4(keccak256("fillOrder((address,address,address,address,uint256,uint256,uint256,uint256,uint256,uint256,bytes,bytes),uint256,bytes)"));
+
+    // fillOrderNoThrow
+    bytes4 constant public FILL_ORDER_NO_THROW_SELECTOR = 0x3e228bae;
+    bytes4 constant public FILL_ORDER_NO_THROW_SELECTOR_GENERATOR = bytes4(keccak256("fillOrderNoThrow((address,address,address,address,uint256,uint256,uint256,uint256,uint256,uint256,bytes,bytes),uint256,bytes)"));
+
+    // filled
+    bytes4 constant public FILLED_SELECTOR = 0x288cdc91;
+    bytes4 constant public FILLED_SELECTOR_GENERATOR = bytes4(keccak256("filled(bytes32)"));
+
+    // getAssetProxy
+    bytes4 constant public GET_ASSET_PROXY_SELECTOR = 0x60704108;
+    bytes4 constant public GET_ASSET_PROXY_SELECTOR_GENERATOR = bytes4(keccak256("getAssetProxy(bytes4)"));
+
+    // getOrderInfo
+    bytes4 constant public GET_ORDER_INFO_SELECTOR = 0xc75e0a81;
+    bytes4 constant public GET_ORDER_INFO_SELECTOR_GENERATOR = bytes4(keccak256("getOrderInfo((address,address,address,address,uint256,uint256,uint256,uint256,uint256,uint256,bytes,bytes))"));
+
+    // getOrdersInfo
+    bytes4 constant public GET_ORDERS_INFO_SELECTOR = 0x7e9d74dc;
+    bytes4 constant public GET_ORDERS_INFO_SELECTOR_GENERATOR = bytes4(keccak256("getOrdersInfo((address,address,address,address,uint256,uint256,uint256,uint256,uint256,uint256,bytes,bytes)[])"));
+
+    // isValidSignature
+    bytes4 constant public IS_VALID_SIGNATURE_SELECTOR = 0x93634702;
+    bytes4 constant public IS_VALID_SIGNATURE_SELECTOR_GENERATOR = bytes4(keccak256("isValidSignature(bytes32,address,bytes)"));
+
+    // marketBuyOrders
+    bytes4 constant public MARKET_BUY_ORDERS_SELECTOR = 0xe5fa431b;
+    bytes4 constant public MARKET_BUY_ORDERS_SELECTOR_GENERATOR = bytes4(keccak256("marketBuyOrders((address,address,address,address,uint256,uint256,uint256,uint256,uint256,uint256,bytes,bytes)[],uint256,bytes[])"));
+
+    // marketBuyOrdersNoThrow
+    bytes4 constant public MARKET_BUY_ORDERS_NO_THROW_SELECTOR = 0xa3e20380;
+    bytes4 constant public MARKET_BUY_ORDERS_NO_THROW_SELECTOR_GENERATOR = bytes4(keccak256("marketBuyOrdersNoThrow((address,address,address,address,uint256,uint256,uint256,uint256,uint256,uint256,bytes,bytes)[],uint256,bytes[])"));
+
+    // marketSellOrders
+    bytes4 constant public MARKET_SELL_ORDERS_SELECTOR = 0x7e1d9808;
+    bytes4 constant public MARKET_SELL_ORDERS_SELECTOR_GENERATOR = bytes4(keccak256("marketSellOrders((address,address,address,address,uint256,uint256,uint256,uint256,uint256,uint256,bytes,bytes)[],uint256,bytes[])"));
+
+    // marketSellOrdersNoThrow
+    bytes4 constant public MARKET_SELL_ORDERS_NO_THROW_SELECTOR = 0xdd1c7d18;
+    bytes4 constant public MARKET_SELL_ORDERS_NO_THROW_SELECTOR_GENERATOR = bytes4(keccak256("marketSellOrdersNoThrow((address,address,address,address,uint256,uint256,uint256,uint256,uint256,uint256,bytes,bytes)[],uint256,bytes[])"));
+
+    // matchOrders
+    bytes4 constant public MATCH_ORDERS_SELECTOR = 0x3c28d861;
+    bytes4 constant public MATCH_ORDERS_SELECTOR_GENERATOR = bytes4(keccak256("matchOrders((address,address,address,address,uint256,uint256,uint256,uint256,uint256,uint256,bytes,bytes),(address,address,address,address,uint256,uint256,uint256,uint256,uint256,uint256,bytes,bytes),bytes,bytes)"));
+
+    // orderEpoch
+    bytes4 constant public ORDER_EPOCH_SELECTOR = 0xd9bfa73e;
+    bytes4 constant public ORDER_EPOCH_SELECTOR_GENERATOR = bytes4(keccak256("orderEpoch(address,address)"));
+
+    // owner
+    bytes4 constant public OWNER_SELECTOR = 0x8da5cb5b;
+    bytes4 constant public OWNER_SELECTOR_GENERATOR = bytes4(keccak256("owner()"));
+
+    // preSign
+    bytes4 constant public PRE_SIGN_SELECTOR = 0x3683ef8e;
+    bytes4 constant public PRE_SIGN_SELECTOR_GENERATOR = bytes4(keccak256("preSign(bytes32,address,bytes)"));
+
+    // preSigned
+    bytes4 constant public PRE_SIGNED_SELECTOR = 0x82c174d0;
+    bytes4 constant public PRE_SIGNED_SELECTOR_GENERATOR = bytes4(keccak256("preSigned(bytes32,address)"));
+
+    // registerAssetProxy
+    bytes4 constant public REGISTER_ASSET_PROXY_SELECTOR = 0xc585bb93;
+    bytes4 constant public REGISTER_ASSET_PROXY_SELECTOR_GENERATOR = bytes4(keccak256("registerAssetProxy(address)"));
+
+    // setSignatureValidatorApproval
+    bytes4 constant public SET_SIGNATURE_VALIDATOR_APPROVAL_SELECTOR = 0x77fcce68;
+    bytes4 constant public SET_SIGNATURE_VALIDATOR_APPROVAL_SELECTOR_GENERATOR = bytes4(keccak256("setSignatureValidatorApproval(address,bool)"));
+
+    // transactions
+    bytes4 constant public TRANSACTIONS_SELECTOR = 0x642f2eaf;
+    bytes4 constant public TRANSACTIONS_SELECTOR_GENERATOR = bytes4(keccak256("transactions(bytes32)"));
+
+    // transferOwnership
+    bytes4 constant public TRANSFER_OWNERSHIP_SELECTOR = 0xf2fde38b;
+    bytes4 constant public TRANSFER_OWNERSHIP_SELECTOR_GENERATOR = bytes4(keccak256("transferOwnership(address)"));
+}
\ No newline at end of file
diff --git a/contracts/libs/contracts/libs/LibFillResults.sol b/contracts/libs/contracts/libs/LibFillResults.sol
index fbd9950bf..74b7f7984 100644
--- a/contracts/libs/contracts/libs/LibFillResults.sol
+++ b/contracts/libs/contracts/libs/LibFillResults.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity 0.4.24;
+pragma solidity ^0.4.24;
 
 import "@0x/contracts-utils/contracts/utils/SafeMath/SafeMath.sol";
 
diff --git a/contracts/libs/contracts/libs/LibMath.sol b/contracts/libs/contracts/libs/LibMath.sol
index b24876a9c..f14b1b34d 100644
--- a/contracts/libs/contracts/libs/LibMath.sol
+++ b/contracts/libs/contracts/libs/LibMath.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity 0.4.24;
+pragma solidity ^0.4.24;
 
 import "@0x/contracts-utils/contracts/utils/SafeMath/SafeMath.sol";
 
diff --git a/contracts/libs/contracts/libs/LibOrder.sol b/contracts/libs/contracts/libs/LibOrder.sol
index 0fe7c2161..fcf5da5fb 100644
--- a/contracts/libs/contracts/libs/LibOrder.sol
+++ b/contracts/libs/contracts/libs/LibOrder.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity 0.4.24;
+pragma solidity ^0.4.24;
 
 import "./LibEIP712.sol";
 
diff --git a/contracts/libs/package.json b/contracts/libs/package.json
index fa4b6e523..ce7b97502 100644
--- a/contracts/libs/package.json
+++ b/contracts/libs/package.json
@@ -19,7 +19,8 @@
         "test:profiler": "SOLIDITY_PROFILER=true run-s build run_mocha profiler:report:html",
         "test:trace": "SOLIDITY_REVERT_TRACE=true run-s build run_mocha",
         "run_mocha": "mocha --require source-map-support/register --require make-promises-safe 'lib/test/**/*.js' --timeout 100000 --bail --exit",
-        "compile": "sol-compiler --contracts-dir contracts",
+        "compile": "sol-compiler",
+        "watch": "sol-compiler -w",
         "clean": "shx rm -rf lib generated-artifacts generated-wrappers",
         "generate_contract_wrappers": "abi-gen --abis  ${npm_package_config_abis} --template ../../node_modules/@0x/abi-gen-templates/contract.handlebars --partials '../../node_modules/@0x/abi-gen-templates/partials/**/*.handlebars' --output generated-wrappers --backend ethers",
         "lint": "tslint --format stylish --project . --exclude ./generated-wrappers/**/* --exclude ./generated-artifacts/**/* --exclude **/lib/**/* && yarn lint-contracts",
diff --git a/contracts/multisig/package.json b/contracts/multisig/package.json
index b338f67f7..2d7b4aa05 100644
--- a/contracts/multisig/package.json
+++ b/contracts/multisig/package.json
@@ -19,7 +19,8 @@
         "test:profiler": "SOLIDITY_PROFILER=true run-s build run_mocha profiler:report:html",
         "test:trace": "SOLIDITY_REVERT_TRACE=true run-s build run_mocha",
         "run_mocha": "mocha --require source-map-support/register --require make-promises-safe 'lib/test/**/*.js' --timeout 100000 --bail --exit",
-        "compile": "sol-compiler --contracts-dir contracts",
+        "compile": "sol-compiler",
+        "watch": "sol-compiler -w",
         "clean": "shx rm -rf lib generated-artifacts generated-wrappers",
         "generate_contract_wrappers": "abi-gen --abis  ${npm_package_config_abis} --template ../../packages/abi-gen-templates/contract.handlebars --partials '../../packages/abi-gen-templates/partials/**/*.handlebars' --output generated-wrappers --backend ethers",
         "lint": "tslint --format stylish --project . --exclude ./generated-wrappers/**/* --exclude ./generated-artifacts/**/* --exclude **/lib/**/* && yarn lint-contracts",
diff --git a/contracts/multisig/src/index.ts b/contracts/multisig/src/index.ts
new file mode 100644
index 000000000..d55f08ea2
--- /dev/null
+++ b/contracts/multisig/src/index.ts
@@ -0,0 +1,2 @@
+export * from './artifacts';
+export * from './wrappers';
diff --git a/contracts/protocol/CHANGELOG.json b/contracts/protocol/CHANGELOG.json
index 5c3798a69..e283d7917 100644
--- a/contracts/protocol/CHANGELOG.json
+++ b/contracts/protocol/CHANGELOG.json
@@ -1,5 +1,22 @@
 [
     {
+        "version": "2.2.0",
+        "changes": [
+            {
+                "note": "Added LibAddressArray",
+                "pr": 1383
+            },
+            {
+                "note": "Add validation and comments to MultiAssetProxy",
+                "pr": 1455
+            },
+            {
+                "note": "Move OrderValidator to extensions",
+                "pr": 1464
+            }
+        ]
+    },
+    {
         "timestamp": 1544741676,
         "version": "2.1.59",
         "changes": [
diff --git a/contracts/protocol/compiler.json b/contracts/protocol/compiler.json
index c05d62aba..10e5bb0a1 100644
--- a/contracts/protocol/compiler.json
+++ b/contracts/protocol/compiler.json
@@ -25,7 +25,6 @@
         "Exchange",
         "MixinAuthorizable",
         "MultiAssetProxy",
-        "OrderValidator",
         "TestAssetProxyOwner",
         "TestAssetProxyDispatcher",
         "TestExchangeInternals",
diff --git a/contracts/protocol/contracts/protocol/AssetProxy/MixinAuthorizable.sol b/contracts/protocol/contracts/protocol/AssetProxy/MixinAuthorizable.sol
index 08f9b94dc..b610ef709 100644
--- a/contracts/protocol/contracts/protocol/AssetProxy/MixinAuthorizable.sol
+++ b/contracts/protocol/contracts/protocol/AssetProxy/MixinAuthorizable.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity 0.4.24;
+pragma solidity ^0.4.24;
 
 import "@0x/contracts-utils/contracts/utils/Ownable/Ownable.sol";
 import "./mixins/MAuthorizable.sol";
diff --git a/contracts/protocol/contracts/protocol/AssetProxy/MultiAssetProxy.sol b/contracts/protocol/contracts/protocol/AssetProxy/MultiAssetProxy.sol
index 42231e73b..5f559163c 100644
--- a/contracts/protocol/contracts/protocol/AssetProxy/MultiAssetProxy.sol
+++ b/contracts/protocol/contracts/protocol/AssetProxy/MultiAssetProxy.sol
@@ -33,6 +33,9 @@ contract MultiAssetProxy is
     function ()
         external
     {
+        // NOTE: The below assembly assumes that clients do some input validation and that the input is properly encoded according to the AbiV2 specification.
+        // It is technically possible for inputs with very large lengths and offsets to cause overflows. However, this would make the calldata prohibitively
+        // expensive and we therefore do not check for overflows in these scenarios.
         assembly {
             // The first 4 bytes of calldata holds the function selector
             let selector := and(calldataload(0), 0xffffffff00000000000000000000000000000000000000000000000000000000)
@@ -145,7 +148,7 @@ contract MultiAssetProxy is
                 let nestedAssetDataLen := calldataload(sub(nestedAssetDataContentsStart, 32))
 
                 // Revert if number of elements in `amounts` differs from number of elements in `nestedAssetData`
-                if iszero(eq(amountsLen, nestedAssetDataLen)) {
+                if sub(amountsLen, nestedAssetDataLen) {
                     // Revert with `Error("LENGTH_MISMATCH")`
                     mstore(0, 0x08c379a000000000000000000000000000000000000000000000000000000000)
                     mstore(32, 0x0000002000000000000000000000000000000000000000000000000000000000)
@@ -181,8 +184,11 @@ contract MultiAssetProxy is
                     let amountsElement := calldataload(add(amountsContentsStart, i))
                     let totalAmount := mul(amountsElement, amount)
 
-                    // Revert if multiplication resulted in an overflow
-                    if iszero(eq(div(totalAmount, amount), amountsElement)) {
+                    // Revert if `amount` != 0 and multiplication resulted in an overflow 
+                    if iszero(or(
+                        iszero(amount),
+                        eq(div(totalAmount, amount), amountsElement)
+                    )) {
                         // Revert with `Error("UINT256_OVERFLOW")`
                         mstore(0, 0x08c379a000000000000000000000000000000000000000000000000000000000)
                         mstore(32, 0x0000002000000000000000000000000000000000000000000000000000000000)
@@ -230,7 +236,7 @@ contract MultiAssetProxy is
 
                     // Only load `assetProxy` if `currentAssetProxyId` does not equal `assetProxyId`
                     // We do not need to check if `currentAssetProxyId` is 0 since `assetProxy` is also initialized to 0
-                    if iszero(eq(currentAssetProxyId, assetProxyId)) {
+                    if sub(currentAssetProxyId, assetProxyId) {
                         // Update `assetProxyId`
                         assetProxyId := currentAssetProxyId
                         // To lookup a value in a mapping, we load from the storage location keccak256(k, p),
diff --git a/contracts/protocol/contracts/protocol/AssetProxy/mixins/MAuthorizable.sol b/contracts/protocol/contracts/protocol/AssetProxy/mixins/MAuthorizable.sol
index fe77048ce..6c3f70500 100644
--- a/contracts/protocol/contracts/protocol/AssetProxy/mixins/MAuthorizable.sol
+++ b/contracts/protocol/contracts/protocol/AssetProxy/mixins/MAuthorizable.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity 0.4.24;
+pragma solidity ^0.4.24;
 
 import "@0x/contracts-interfaces/contracts/protocol/AssetProxy/IAuthorizable.sol";
 
diff --git a/contracts/protocol/contracts/protocol/Exchange/MixinAssetProxyDispatcher.sol b/contracts/protocol/contracts/protocol/Exchange/MixinAssetProxyDispatcher.sol
index 36ab39b45..2922a8c1a 100644
--- a/contracts/protocol/contracts/protocol/Exchange/MixinAssetProxyDispatcher.sol
+++ b/contracts/protocol/contracts/protocol/Exchange/MixinAssetProxyDispatcher.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity 0.4.24;
+pragma solidity ^0.4.24;
 
 import "@0x/contracts-utils/contracts/utils/Ownable/Ownable.sol";
 import "./mixins/MAssetProxyDispatcher.sol";
diff --git a/contracts/protocol/contracts/protocol/Exchange/MixinExchangeCore.sol b/contracts/protocol/contracts/protocol/Exchange/MixinExchangeCore.sol
index 68d6a3897..72bcebc62 100644
--- a/contracts/protocol/contracts/protocol/Exchange/MixinExchangeCore.sol
+++ b/contracts/protocol/contracts/protocol/Exchange/MixinExchangeCore.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity 0.4.24;
+pragma solidity ^0.4.24;
 pragma experimental ABIEncoderV2;
 
 import "@0x/contracts-utils/contracts/utils/ReentrancyGuard/ReentrancyGuard.sol";
diff --git a/contracts/protocol/contracts/protocol/Exchange/MixinMatchOrders.sol b/contracts/protocol/contracts/protocol/Exchange/MixinMatchOrders.sol
index fc6d73482..2627b82fd 100644
--- a/contracts/protocol/contracts/protocol/Exchange/MixinMatchOrders.sol
+++ b/contracts/protocol/contracts/protocol/Exchange/MixinMatchOrders.sol
@@ -11,7 +11,7 @@
   limitations under the License.
 */
 
-pragma solidity 0.4.24;
+pragma solidity ^0.4.24;
 pragma experimental ABIEncoderV2;
 
 import "@0x/contracts-utils/contracts/utils/ReentrancyGuard/ReentrancyGuard.sol";
diff --git a/contracts/protocol/contracts/protocol/Exchange/MixinSignatureValidator.sol b/contracts/protocol/contracts/protocol/Exchange/MixinSignatureValidator.sol
index 80b4c0755..b40aa1412 100644
--- a/contracts/protocol/contracts/protocol/Exchange/MixinSignatureValidator.sol
+++ b/contracts/protocol/contracts/protocol/Exchange/MixinSignatureValidator.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity 0.4.24;
+pragma solidity ^0.4.24;
 
 import "@0x/contracts-utils/contracts/utils/LibBytes/LibBytes.sol";
 import "@0x/contracts-utils/contracts/utils/ReentrancyGuard/ReentrancyGuard.sol";
diff --git a/contracts/protocol/contracts/protocol/Exchange/MixinTransactions.sol b/contracts/protocol/contracts/protocol/Exchange/MixinTransactions.sol
index 87c614382..1ac5b1a5e 100644
--- a/contracts/protocol/contracts/protocol/Exchange/MixinTransactions.sol
+++ b/contracts/protocol/contracts/protocol/Exchange/MixinTransactions.sol
@@ -15,7 +15,7 @@
   limitations under the License.
 
 */
-pragma solidity 0.4.24;
+pragma solidity ^0.4.24;
 
 import "@0x/contracts-libs/contracts/libs/LibExchangeErrors.sol";
 import "./mixins/MSignatureValidator.sol";
diff --git a/contracts/protocol/contracts/protocol/Exchange/MixinWrapperFunctions.sol b/contracts/protocol/contracts/protocol/Exchange/MixinWrapperFunctions.sol
index 2d43432ff..6fc6ee999 100644
--- a/contracts/protocol/contracts/protocol/Exchange/MixinWrapperFunctions.sol
+++ b/contracts/protocol/contracts/protocol/Exchange/MixinWrapperFunctions.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity 0.4.24;
+pragma solidity ^0.4.24;
 pragma experimental ABIEncoderV2;
 
 import "@0x/contracts-utils/contracts/utils/ReentrancyGuard/ReentrancyGuard.sol";
diff --git a/contracts/protocol/contracts/protocol/Exchange/mixins/MAssetProxyDispatcher.sol b/contracts/protocol/contracts/protocol/Exchange/mixins/MAssetProxyDispatcher.sol
index fe3d03326..05c2c4c0b 100644
--- a/contracts/protocol/contracts/protocol/Exchange/mixins/MAssetProxyDispatcher.sol
+++ b/contracts/protocol/contracts/protocol/Exchange/mixins/MAssetProxyDispatcher.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity 0.4.24;
+pragma solidity ^0.4.24;
 
 import "@0x/contracts-interfaces/contracts/protocol/Exchange/IAssetProxyDispatcher.sol";
 
diff --git a/contracts/protocol/contracts/protocol/Exchange/mixins/MExchangeCore.sol b/contracts/protocol/contracts/protocol/Exchange/mixins/MExchangeCore.sol
index 215284900..09dc491cd 100644
--- a/contracts/protocol/contracts/protocol/Exchange/mixins/MExchangeCore.sol
+++ b/contracts/protocol/contracts/protocol/Exchange/mixins/MExchangeCore.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity 0.4.24;
+pragma solidity ^0.4.24;
 pragma experimental ABIEncoderV2;
 
 import "@0x/contracts-libs/contracts/libs/LibOrder.sol";
diff --git a/contracts/protocol/contracts/protocol/Exchange/mixins/MMatchOrders.sol b/contracts/protocol/contracts/protocol/Exchange/mixins/MMatchOrders.sol
index 1eb4be329..56ee895c4 100644
--- a/contracts/protocol/contracts/protocol/Exchange/mixins/MMatchOrders.sol
+++ b/contracts/protocol/contracts/protocol/Exchange/mixins/MMatchOrders.sol
@@ -15,7 +15,7 @@
   limitations under the License.
 
 */
-pragma solidity 0.4.24;
+pragma solidity ^0.4.24;
 pragma experimental ABIEncoderV2;
 
 import "@0x/contracts-libs/contracts/libs/LibOrder.sol";
diff --git a/contracts/protocol/contracts/protocol/Exchange/mixins/MSignatureValidator.sol b/contracts/protocol/contracts/protocol/Exchange/mixins/MSignatureValidator.sol
index a933976d1..6407760d4 100644
--- a/contracts/protocol/contracts/protocol/Exchange/mixins/MSignatureValidator.sol
+++ b/contracts/protocol/contracts/protocol/Exchange/mixins/MSignatureValidator.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity 0.4.24;
+pragma solidity ^0.4.24;
 
 import "@0x/contracts-interfaces/contracts/protocol/Exchange/ISignatureValidator.sol";
 
diff --git a/contracts/protocol/contracts/protocol/Exchange/mixins/MTransactions.sol b/contracts/protocol/contracts/protocol/Exchange/mixins/MTransactions.sol
index a6b0fdc85..04dd716d7 100644
--- a/contracts/protocol/contracts/protocol/Exchange/mixins/MTransactions.sol
+++ b/contracts/protocol/contracts/protocol/Exchange/mixins/MTransactions.sol
@@ -15,7 +15,7 @@
   limitations under the License.
 
 */
-pragma solidity 0.4.24;
+pragma solidity ^0.4.24;
 
 import "@0x/contracts-interfaces/contracts/protocol/Exchange/ITransactions.sol";
 
diff --git a/contracts/protocol/contracts/protocol/Exchange/mixins/MWrapperFunctions.sol b/contracts/protocol/contracts/protocol/Exchange/mixins/MWrapperFunctions.sol
index 101e7cb82..2ff3b8790 100644
--- a/contracts/protocol/contracts/protocol/Exchange/mixins/MWrapperFunctions.sol
+++ b/contracts/protocol/contracts/protocol/Exchange/mixins/MWrapperFunctions.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity 0.4.24;
+pragma solidity ^0.4.24;
 pragma experimental ABIEncoderV2;
 
 import "@0x/contracts-libs/contracts/libs/LibOrder.sol";
diff --git a/contracts/protocol/package.json b/contracts/protocol/package.json
index 838189371..891838e54 100644
--- a/contracts/protocol/package.json
+++ b/contracts/protocol/package.json
@@ -19,7 +19,8 @@
         "test:profiler": "SOLIDITY_PROFILER=true run-s build run_mocha profiler:report:html",
         "test:trace": "SOLIDITY_REVERT_TRACE=true run-s build run_mocha",
         "run_mocha": "mocha --require source-map-support/register --require make-promises-safe 'lib/test/**/*.js' --timeout 100000 --bail --exit",
-        "compile": "sol-compiler --contracts-dir contracts",
+        "compile": "sol-compiler",
+        "watch": "sol-compiler -w",
         "clean": "shx rm -rf lib generated-artifacts generated-wrappers",
         "generate_contract_wrappers": "abi-gen --abis  ${npm_package_config_abis} --template ../../node_modules/@0x/abi-gen-templates/contract.handlebars --partials '../../node_modules/@0x/abi-gen-templates/partials/**/*.handlebars' --output generated-wrappers --backend ethers",
         "lint": "tslint --format stylish --project . --exclude ./generated-wrappers/**/* --exclude ./generated-artifacts/**/* --exclude **/lib/**/* && yarn lint-contracts",
@@ -31,7 +32,7 @@
         "lint-contracts": "solhint -c ../.solhint.json contracts/**/**/**/**/*.sol"
     },
     "config": {
-        "abis": "generated-artifacts/@(AssetProxyOwner|ERC20Proxy|ERC721Proxy|Exchange|MixinAuthorizable|MultiAssetProxy|OrderValidator|TestSignatureValidator|TestAssetProxyOwner|TestAssetProxyDispatcher|TestExchangeInternals|TestStaticCallReceiver).json"
+        "abis": "generated-artifacts/@(AssetProxyOwner|ERC20Proxy|ERC721Proxy|Exchange|MixinAuthorizable|MultiAssetProxy|TestSignatureValidator|TestAssetProxyOwner|TestAssetProxyDispatcher|TestExchangeInternals|TestStaticCallReceiver).json"
     },
     "repository": {
         "type": "git",
@@ -44,7 +45,6 @@
     "homepage": "https://github.com/0xProject/0x-monorepo/contracts/protocol/README.md",
     "devDependencies": {
         "@0x/abi-gen": "^1.0.19",
-        "@0x/contracts-test-utils": "^1.0.2",
         "@0x/dev-utils": "^1.0.21",
         "@0x/sol-compiler": "^1.1.16",
         "@0x/sol-cov": "^2.1.16",
@@ -75,6 +75,7 @@
         "@0x/contracts-interfaces": "^1.0.2",
         "@0x/contracts-libs": "^1.0.2",
         "@0x/contracts-multisig": "^1.0.2",
+        "@0x/contracts-test-utils": "^1.0.2",
         "@0x/contracts-tokens": "^1.0.2",
         "@0x/contracts-utils": "^1.0.2",
         "@0x/order-utils": "^3.0.7",
diff --git a/contracts/protocol/src/artifacts/index.ts b/contracts/protocol/src/artifacts/index.ts
index 1d53ceb04..c5d12f10b 100644
--- a/contracts/protocol/src/artifacts/index.ts
+++ b/contracts/protocol/src/artifacts/index.ts
@@ -6,7 +6,6 @@ import * as ERC721Proxy from '../../generated-artifacts/ERC721Proxy.json';
 import * as Exchange from '../../generated-artifacts/Exchange.json';
 import * as MixinAuthorizable from '../../generated-artifacts/MixinAuthorizable.json';
 import * as MultiAssetProxy from '../../generated-artifacts/MultiAssetProxy.json';
-import * as OrderValidator from '../../generated-artifacts/OrderValidator.json';
 import * as TestAssetProxyDispatcher from '../../generated-artifacts/TestAssetProxyDispatcher.json';
 import * as TestAssetProxyOwner from '../../generated-artifacts/TestAssetProxyOwner.json';
 import * as TestExchangeInternals from '../../generated-artifacts/TestExchangeInternals.json';
@@ -20,7 +19,6 @@ export const artifacts = {
     Exchange: Exchange as ContractArtifact,
     MixinAuthorizable: MixinAuthorizable as ContractArtifact,
     MultiAssetProxy: MultiAssetProxy as ContractArtifact,
-    OrderValidator: OrderValidator as ContractArtifact,
     TestAssetProxyDispatcher: TestAssetProxyDispatcher as ContractArtifact,
     TestAssetProxyOwner: TestAssetProxyOwner as ContractArtifact,
     TestExchangeInternals: TestExchangeInternals as ContractArtifact,
diff --git a/contracts/protocol/src/wrappers/index.ts b/contracts/protocol/src/wrappers/index.ts
index ac951d269..01b121054 100644
--- a/contracts/protocol/src/wrappers/index.ts
+++ b/contracts/protocol/src/wrappers/index.ts
@@ -3,7 +3,6 @@ export * from '../../generated-wrappers/erc20_proxy';
 export * from '../../generated-wrappers/erc721_proxy';
 export * from '../../generated-wrappers/exchange';
 export * from '../../generated-wrappers/mixin_authorizable';
-export * from '../../generated-wrappers/order_validator';
 export * from '../../generated-wrappers/test_asset_proxy_dispatcher';
 export * from '../../generated-wrappers/test_asset_proxy_owner';
 export * from '../../generated-wrappers/test_exchange_internals';
diff --git a/contracts/protocol/test/asset_proxy/proxies.ts b/contracts/protocol/test/asset_proxy/proxies.ts
index c4bd95905..89c8b390c 100644
--- a/contracts/protocol/test/asset_proxy/proxies.ts
+++ b/contracts/protocol/test/asset_proxy/proxies.ts
@@ -12,6 +12,7 @@ import {
 import {
     artifacts as tokensArtifacts,
     DummyERC20TokenContract,
+    DummyERC20TokenTransferEventArgs,
     DummyERC721ReceiverContract,
     DummyERC721TokenContract,
     DummyMultipleReturnERC20TokenContract,
@@ -22,6 +23,7 @@ import { assetDataUtils } from '@0x/order-utils';
 import { RevertReason } from '@0x/types';
 import { BigNumber } from '@0x/utils';
 import * as chai from 'chai';
+import { LogWithDecodedArgs } from 'ethereum-types';
 import * as _ from 'lodash';
 
 import { ERC20ProxyContract } from '../../generated-wrappers/erc20_proxy';
@@ -738,6 +740,36 @@ describe('Asset Transfer Proxies', () => {
                     erc20Balances[toAddress][erc20TokenA.address].add(totalAmount),
                 );
             });
+            it('should dispatch an ERC20 transfer when input amount is 0', async () => {
+                const inputAmount = constants.ZERO_AMOUNT;
+                const erc20Amount = new BigNumber(10);
+                const erc20AssetData = assetDataUtils.encodeERC20AssetData(erc20TokenA.address);
+                const amounts = [erc20Amount];
+                const nestedAssetData = [erc20AssetData];
+                const assetData = assetDataInterface.MultiAsset.getABIEncodedTransactionData(amounts, nestedAssetData);
+                const data = assetProxyInterface.transferFrom.getABIEncodedTransactionData(
+                    assetData,
+                    fromAddress,
+                    toAddress,
+                    inputAmount,
+                );
+                const erc20Balances = await erc20Wrapper.getBalancesAsync();
+                const logDecoder = new LogDecoder(web3Wrapper, { ...artifacts, ...tokensArtifacts });
+                const tx = await logDecoder.getTxWithDecodedLogsAsync(
+                    await web3Wrapper.sendTransactionAsync({
+                        to: multiAssetProxy.address,
+                        data,
+                        from: authorized,
+                    }),
+                );
+                expect(tx.logs.length).to.be.equal(1);
+                const log = tx.logs[0] as LogWithDecodedArgs<DummyERC20TokenTransferEventArgs>;
+                const transferEventName = 'Transfer';
+                expect(log.event).to.equal(transferEventName);
+                expect(log.args._value).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+                const newBalances = await erc20Wrapper.getBalancesAsync();
+                expect(newBalances).to.deep.equal(erc20Balances);
+            });
             it('should successfully transfer multiple of the same ERC20 token', async () => {
                 const inputAmount = new BigNumber(1);
                 const erc20Amount1 = new BigNumber(10);
diff --git a/contracts/protocol/tsconfig.json b/contracts/protocol/tsconfig.json
index 989d3ef2b..db872fc32 100644
--- a/contracts/protocol/tsconfig.json
+++ b/contracts/protocol/tsconfig.json
@@ -13,7 +13,6 @@
         "./generated-artifacts/Exchange.json",
         "./generated-artifacts/MixinAuthorizable.json",
         "./generated-artifacts/MultiAssetProxy.json",
-        "./generated-artifacts/OrderValidator.json",
         "./generated-artifacts/TestAssetProxyDispatcher.json",
         "./generated-artifacts/TestAssetProxyOwner.json",
         "./generated-artifacts/TestExchangeInternals.json",
diff --git a/contracts/test-utils/src/constants.ts b/contracts/test-utils/src/constants.ts
index d2c3ab512..f631dc81a 100644
--- a/contracts/test-utils/src/constants.ts
+++ b/contracts/test-utils/src/constants.ts
@@ -29,6 +29,7 @@ export const constants = {
     MAX_TOKEN_TRANSFERFROM_GAS: 80000,
     MAX_TOKEN_APPROVE_GAS: 60000,
     MAX_TRANSFER_FROM_GAS: 150000,
+    MAX_MATCH_ORDERS_GAS: 400000,
     DUMMY_TOKEN_NAME: '',
     DUMMY_TOKEN_SYMBOL: '',
     DUMMY_TOKEN_DECIMALS: new BigNumber(18),
diff --git a/contracts/test-utils/src/types.ts b/contracts/test-utils/src/types.ts
index d738fcd4e..1630eab0d 100644
--- a/contracts/test-utils/src/types.ts
+++ b/contracts/test-utils/src/types.ts
@@ -104,6 +104,7 @@ export enum ContractName {
     Authorizable = 'Authorizable',
     Whitelist = 'Whitelist',
     Forwarder = 'Forwarder',
+    BalanceThresholdFilter = 'BalanceThresholdFilter',
 }
 
 export interface SignedTransaction {
diff --git a/contracts/tokens/contracts/tokens/ERC20Token/ERC20Token.sol b/contracts/tokens/contracts/tokens/ERC20Token/ERC20Token.sol
index 725d304df..190eead76 100644
--- a/contracts/tokens/contracts/tokens/ERC20Token/ERC20Token.sol
+++ b/contracts/tokens/contracts/tokens/ERC20Token/ERC20Token.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity 0.4.24;
+pragma solidity ^0.4.24;
 
 import "./IERC20Token.sol";
 
diff --git a/contracts/tokens/contracts/tokens/ERC20Token/IERC20Token.sol b/contracts/tokens/contracts/tokens/ERC20Token/IERC20Token.sol
index 258d47393..9f9b89585 100644
--- a/contracts/tokens/contracts/tokens/ERC20Token/IERC20Token.sol
+++ b/contracts/tokens/contracts/tokens/ERC20Token/IERC20Token.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity 0.4.24;
+pragma solidity ^0.4.24;
 
 
 contract IERC20Token {
diff --git a/contracts/tokens/contracts/tokens/ERC20Token/MintableERC20Token.sol b/contracts/tokens/contracts/tokens/ERC20Token/MintableERC20Token.sol
index 58bccb5a1..a66031f03 100644
--- a/contracts/tokens/contracts/tokens/ERC20Token/MintableERC20Token.sol
+++ b/contracts/tokens/contracts/tokens/ERC20Token/MintableERC20Token.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity 0.4.24;
+pragma solidity ^0.4.24;
 
 import "@0x/contracts-utils/contracts/utils/SafeMath/SafeMath.sol";
 import "./UnlimitedAllowanceERC20Token.sol";
diff --git a/contracts/tokens/contracts/tokens/ERC20Token/UnlimitedAllowanceERC20Token.sol b/contracts/tokens/contracts/tokens/ERC20Token/UnlimitedAllowanceERC20Token.sol
index 2e5bd4348..869d16147 100644
--- a/contracts/tokens/contracts/tokens/ERC20Token/UnlimitedAllowanceERC20Token.sol
+++ b/contracts/tokens/contracts/tokens/ERC20Token/UnlimitedAllowanceERC20Token.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity 0.4.24;
+pragma solidity ^0.4.24;
 
 import "../ERC20Token/ERC20Token.sol";
 
diff --git a/contracts/tokens/contracts/tokens/ERC721Token/ERC721Token.sol b/contracts/tokens/contracts/tokens/ERC721Token/ERC721Token.sol
index 600cee1ab..c46bd0af4 100644
--- a/contracts/tokens/contracts/tokens/ERC721Token/ERC721Token.sol
+++ b/contracts/tokens/contracts/tokens/ERC721Token/ERC721Token.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity 0.4.24;
+pragma solidity ^0.4.24;
 
 import "./IERC721Token.sol";
 import "./IERC721Receiver.sol";
diff --git a/contracts/tokens/contracts/tokens/ERC721Token/IERC721Receiver.sol b/contracts/tokens/contracts/tokens/ERC721Token/IERC721Receiver.sol
index 8e0e32ab2..c3ad35ede 100644
--- a/contracts/tokens/contracts/tokens/ERC721Token/IERC721Receiver.sol
+++ b/contracts/tokens/contracts/tokens/ERC721Token/IERC721Receiver.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity 0.4.24;
+pragma solidity ^0.4.24;
 
 
 contract IERC721Receiver {
diff --git a/contracts/tokens/contracts/tokens/ERC721Token/IERC721Token.sol b/contracts/tokens/contracts/tokens/ERC721Token/IERC721Token.sol
index ac992c80d..56a3314df 100644
--- a/contracts/tokens/contracts/tokens/ERC721Token/IERC721Token.sol
+++ b/contracts/tokens/contracts/tokens/ERC721Token/IERC721Token.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity 0.4.24;
+pragma solidity ^0.4.24;
 
 
 contract IERC721Token {
diff --git a/contracts/tokens/contracts/tokens/ERC721Token/MintableERC721Token.sol b/contracts/tokens/contracts/tokens/ERC721Token/MintableERC721Token.sol
index bc5cd2cc2..27326d857 100644
--- a/contracts/tokens/contracts/tokens/ERC721Token/MintableERC721Token.sol
+++ b/contracts/tokens/contracts/tokens/ERC721Token/MintableERC721Token.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity 0.4.24;
+pragma solidity ^0.4.24;
 
 import "./ERC721Token.sol";
 
diff --git a/contracts/tokens/contracts/tokens/EtherToken/IEtherToken.sol b/contracts/tokens/contracts/tokens/EtherToken/IEtherToken.sol
index 9e2e68766..32baa3eb0 100644
--- a/contracts/tokens/contracts/tokens/EtherToken/IEtherToken.sol
+++ b/contracts/tokens/contracts/tokens/EtherToken/IEtherToken.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity 0.4.24;
+pragma solidity ^0.4.24;
 
 import "../ERC20Token/IERC20Token.sol";
 
diff --git a/contracts/tokens/package.json b/contracts/tokens/package.json
index 6f8a366dd..79afc4820 100644
--- a/contracts/tokens/package.json
+++ b/contracts/tokens/package.json
@@ -19,7 +19,8 @@
         "test:profiler": "SOLIDITY_PROFILER=true run-s build run_mocha profiler:report:html",
         "test:trace": "SOLIDITY_REVERT_TRACE=true run-s build run_mocha",
         "run_mocha": "mocha --require source-map-support/register --require make-promises-safe 'lib/test/**/*.js' --timeout 100000 --bail --exit",
-        "compile": "sol-compiler --contracts-dir contracts",
+        "compile": "sol-compiler",
+        "watch": "sol-compiler -w",
         "clean": "shx rm -rf lib generated-artifacts generated-wrappers",
         "generate_contract_wrappers": "abi-gen --abis  ${npm_package_config_abis} --template ../../node_modules/@0x/abi-gen-templates/contract.handlebars --partials '../../node_modules/@0x/abi-gen-templates/partials/**/*.handlebars' --output generated-wrappers --backend ethers",
         "lint": "tslint --format stylish --project . --exclude ./generated-wrappers/**/* --exclude ./generated-artifacts/**/* --exclude **/lib/**/* && yarn lint-contracts",
diff --git a/contracts/utils/contracts/utils/LibBytes/LibBytes.sol b/contracts/utils/contracts/utils/LibBytes/LibBytes.sol
index 369f588ad..4ee6228d5 100644
--- a/contracts/utils/contracts/utils/LibBytes/LibBytes.sol
+++ b/contracts/utils/contracts/utils/LibBytes/LibBytes.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity 0.4.24;
+pragma solidity ^0.4.24;
 
 
 library LibBytes {
diff --git a/contracts/utils/contracts/utils/Ownable/IOwnable.sol b/contracts/utils/contracts/utils/Ownable/IOwnable.sol
index 5deb13497..c0cbfddfd 100644
--- a/contracts/utils/contracts/utils/Ownable/IOwnable.sol
+++ b/contracts/utils/contracts/utils/Ownable/IOwnable.sol
@@ -1,4 +1,4 @@
-pragma solidity 0.4.24;
+pragma solidity ^0.4.24;
 
 
 contract IOwnable {
diff --git a/contracts/utils/contracts/utils/Ownable/Ownable.sol b/contracts/utils/contracts/utils/Ownable/Ownable.sol
index 0c830be68..aa74a72d2 100644
--- a/contracts/utils/contracts/utils/Ownable/Ownable.sol
+++ b/contracts/utils/contracts/utils/Ownable/Ownable.sol
@@ -1,4 +1,4 @@
-pragma solidity 0.4.24;
+pragma solidity ^0.4.24;
 
 import "./IOwnable.sol";
 
diff --git a/contracts/utils/contracts/utils/ReentrancyGuard/ReentrancyGuard.sol b/contracts/utils/contracts/utils/ReentrancyGuard/ReentrancyGuard.sol
index 9f98a7a16..1a02c88a4 100644
--- a/contracts/utils/contracts/utils/ReentrancyGuard/ReentrancyGuard.sol
+++ b/contracts/utils/contracts/utils/ReentrancyGuard/ReentrancyGuard.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity 0.4.24;
+pragma solidity ^0.4.24;
 
 
 contract ReentrancyGuard {
diff --git a/contracts/utils/contracts/utils/SafeMath/SafeMath.sol b/contracts/utils/contracts/utils/SafeMath/SafeMath.sol
index 2855edb9d..d7a4a603e 100644
--- a/contracts/utils/contracts/utils/SafeMath/SafeMath.sol
+++ b/contracts/utils/contracts/utils/SafeMath/SafeMath.sol
@@ -1,4 +1,4 @@
-pragma solidity 0.4.24;
+pragma solidity ^0.4.24;
 
 
 contract SafeMath {
diff --git a/contracts/utils/package.json b/contracts/utils/package.json
index a776bdfbb..cf94af0f6 100644
--- a/contracts/utils/package.json
+++ b/contracts/utils/package.json
@@ -19,7 +19,8 @@
         "test:profiler": "SOLIDITY_PROFILER=true run-s build run_mocha profiler:report:html",
         "test:trace": "SOLIDITY_REVERT_TRACE=true run-s build run_mocha",
         "run_mocha": "mocha --require source-map-support/register --require make-promises-safe 'lib/test/**/*.js' --timeout 100000 --bail --exit",
-        "compile": "sol-compiler --contracts-dir contracts",
+        "compile": "sol-compiler",
+        "watch": "sol-compiler -w",
         "clean": "shx rm -rf lib generated-artifacts generated-wrappers",
         "generate_contract_wrappers": "abi-gen --abis  ${npm_package_config_abis} --template ../../node_modules/@0x/abi-gen-templates/contract.handlebars --partials '../../node_modules/@0x/abi-gen-templates/partials/**/*.handlebars' --output generated-wrappers --backend ethers",
         "lint": "tslint --format stylish --project . --exclude ./generated-wrappers/**/* --exclude ./generated-artifacts/**/* --exclude **/lib/**/* && yarn lint-contracts",