Refactor our extensions package

29 files changed, 4362 insertions, 0 deletions

diff --git a/contracts/extensions/.solhint.json b/contracts/extensions/.solhint.json
new file mode 100644
index 000000000..076afe9f3
--- /dev/null
+++ b/contracts/extensions/.solhint.json
@@ -0,0 +1,20 @@
+{
+    "extends": "default",
+    "rules": {
+        "avoid-low-level-calls": false,
+        "avoid-tx-origin": "warn",
+        "bracket-align": false,
+        "code-complexity": false,
+        "const-name-snakecase": "error",
+        "expression-indent": "error",
+        "function-max-lines": false,
+        "func-order": "error",
+        "indent": ["error", 4],
+        "max-line-length": ["warn", 160],
+        "no-inline-assembly": false,
+        "quotes": ["error", "double"],
+        "separate-by-one-line-in-contract": "error",
+        "space-after-comma": "error",
+        "statement-indent": "error"
+    }
+}
diff --git a/contracts/extensions/README.md b/contracts/extensions/README.md
new file mode 100644
index 000000000..820f6e78a
--- /dev/null
+++ b/contracts/extensions/README.md
@@ -0,0 +1,69 @@
+## Contract extensions
+
+Smart contracts that implement extensions for the 0x protocol.
+
+## Usage
+
+Contract extensions of the protocol can be found in the [contracts](./contracts) directory. This directory contains contracts that interact with the 2.0.0 contracts and will be used in production, such as the [Forwarder](https://github.com/0xProject/0x-protocol-specification/blob/master/v2/forwarder-specification.md) contract.
+
+## Bug bounty
+
+A bug bounty for the 2.0.0 contracts is ongoing! Instructions can be found [here](https://0xproject.com/wiki#Bug-Bounty).
+
+## Contributing
+
+We strongly recommend that the community help us make improvements and determine the future direction of the protocol. To report bugs within this package, please create an issue in this repository.
+
+For proposals regarding the 0x protocol's smart contract architecture, message format, or additional functionality, go to the [0x Improvement Proposals (ZEIPs)](https://github.com/0xProject/ZEIPs) repository and follow the contribution guidelines provided therein.
+
+Please read our [contribution guidelines](../../CONTRIBUTING.md) before getting started.
+
+### Install Dependencies
+
+If you don't have yarn workspaces enabled (Yarn < v1.0) - enable them:
+
+```bash
+yarn config set workspaces-experimental true
+```
+
+Then install dependencies
+
+```bash
+yarn install
+```
+
+### Build
+
+To build this package and all other monorepo packages that it depends on, run the following from the monorepo root directory:
+
+```bash
+PKG=@0x/contracts-extensions yarn build
+```
+
+Or continuously rebuild on change:
+
+```bash
+PKG=@0x/contracts-extensions yarn watch
+```
+
+### Clean
+
+```bash
+yarn clean
+```
+
+### Lint
+
+```bash
+yarn lint
+```
+
+### Run Tests
+
+```bash
+yarn test
+```
+
+#### Testing options
+
+Contracts testing options like coverage, profiling, revert traces or backing node choosing - are described [here](../TESTING.md).
diff --git a/contracts/extensions/compiler.json b/contracts/extensions/compiler.json
new file mode 100644
index 000000000..807429976
--- /dev/null
+++ b/contracts/extensions/compiler.json
@@ -0,0 +1,22 @@
+{
+    "artifactsDir": "./generated-artifacts",
+    "contractsDir": "./contracts",
+    "compilerSettings": {
+        "optimizer": {
+            "enabled": true,
+            "runs": 1000000
+        },
+        "outputSelection": {
+            "*": {
+                "*": [
+                    "abi",
+                    "evm.bytecode.object",
+                    "evm.bytecode.sourceMap",
+                    "evm.deployedBytecode.object",
+                    "evm.deployedBytecode.sourceMap"
+                ]
+            }
+        }
+    },
+    "contracts": ["DutchAuction", "Forwarder", "OrderValidator"]
+}
diff --git a/contracts/extensions/contracts/DutchAuction/DutchAuction.sol b/contracts/extensions/contracts/DutchAuction/DutchAuction.sol
new file mode 100644
index 000000000..9c9f3990a
--- /dev/null
+++ b/contracts/extensions/contracts/DutchAuction/DutchAuction.sol
@@ -0,0 +1,205 @@
+/*
+
+  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-interfaces/contracts/protocol/Exchange/IExchange.sol";
+import "@0x/contracts-libs/contracts/libs/LibOrder.sol";
+import "@0x/contracts-tokens/contracts/tokens/ERC20Token/IERC20Token.sol";
+import "@0x/contracts-utils/contracts/utils/LibBytes/LibBytes.sol";
+import "@0x/contracts-utils/contracts/utils/SafeMath/SafeMath.sol";
+
+
+contract DutchAuction is
+    SafeMath
+{
+    using LibBytes for bytes;
+
+    // solhint-disable var-name-mixedcase
+    IExchange internal EXCHANGE;
+
+    struct AuctionDetails {
+        uint256 beginTimeSeconds;    // Auction begin unix timestamp: sellOrder.makerAssetData
+        uint256 endTimeSeconds;      // Auction end unix timestamp: sellOrder.expiryTimeSeconds
+        uint256 beginAmount;         // Auction begin amount: sellOrder.makerAssetData
+        uint256 endAmount;           // Auction end amount: sellOrder.takerAssetAmount
+        uint256 currentAmount;       // Calculated amount given block.timestamp
+        uint256 currentTimeSeconds;  // block.timestamp
+    }
+
+    constructor (address _exchange)
+        public
+    {
+        EXCHANGE = IExchange(_exchange);
+    }
+
+    /// @dev Matches the buy and sell orders at an amount given the following: the current block time, the auction
+    ///      start time and the auction begin amount. The sell order is a an order at the lowest amount
+    ///      at the end of the auction. Excess from the match is transferred to the seller.
+    ///      Over time the price moves from beginAmount to endAmount given the current block.timestamp.
+    ///      sellOrder.expiryTimeSeconds is the end time of the auction.
+    ///      sellOrder.takerAssetAmount is the end amount of the auction (lowest possible amount).
+    ///      sellOrder.makerAssetData is the ABI encoded Asset Proxy data with the following data appended
+    ///      buyOrder.makerAssetData is the buyers bid on the auction, must meet the amount for the current block timestamp
+    ///      (uint256 beginTimeSeconds, uint256 beginAmount).
+    ///      This function reverts in the following scenarios:
+    ///         * Auction has not started (auctionDetails.currentTimeSeconds < auctionDetails.beginTimeSeconds)
+    ///         * Auction has expired (auctionDetails.endTimeSeconds < auctionDetails.currentTimeSeconds)
+    ///         * Amount is invalid: Buy order amount is too low (buyOrder.makerAssetAmount < auctionDetails.currentAmount)
+    ///         * Amount is invalid: Invalid begin amount (auctionDetails.beginAmount > auctionDetails.endAmount)
+    ///         * Any failure in the 0x Match Orders
+    /// @param buyOrder The Buyer's order. This order is for the current expected price of the auction.
+    /// @param sellOrder The Seller's order. This order is for the lowest amount (at the end of the auction).
+    /// @param buySignature Proof that order was created by the buyer.
+    /// @param sellSignature Proof that order was created by the seller.
+    /// @return matchedFillResults amounts filled and fees paid by maker and taker of matched orders.
+    function matchOrders(
+        LibOrder.Order memory buyOrder,
+        LibOrder.Order memory sellOrder,
+        bytes memory buySignature,
+        bytes memory sellSignature
+    )
+        public
+        returns (LibFillResults.MatchedFillResults memory matchedFillResults)
+    {
+        AuctionDetails memory auctionDetails = getAuctionDetails(sellOrder);
+        // Ensure the auction has not yet started
+        require(
+            auctionDetails.currentTimeSeconds >= auctionDetails.beginTimeSeconds,
+            "AUCTION_NOT_STARTED"
+        );
+        // Ensure the auction has not expired. This will fail later in 0x but we can save gas by failing early
+        require(
+            sellOrder.expirationTimeSeconds > auctionDetails.currentTimeSeconds,
+            "AUCTION_EXPIRED"
+        );
+        // Validate the buyer amount is greater than the current auction amount
+        require(
+            buyOrder.makerAssetAmount >= auctionDetails.currentAmount,
+            "INVALID_AMOUNT"
+        );
+        // Match orders, maximally filling `buyOrder`
+        matchedFillResults = EXCHANGE.matchOrders(
+            buyOrder,
+            sellOrder,
+            buySignature,
+            sellSignature
+        );
+        // The difference in sellOrder.takerAssetAmount and current amount is given as spread to the matcher
+        // This may include additional spread from the buyOrder.makerAssetAmount and the currentAmount.
+        // e.g currentAmount is 30, sellOrder.takerAssetAmount is 10 and buyOrder.makerAssetamount is 40.
+        // 10 (40-30) is returned to the buyer, 20 (30-10) sent to the seller and 10 has previously
+        // been transferred to the seller during matchOrders
+        uint256 leftMakerAssetSpreadAmount = matchedFillResults.leftMakerAssetSpreadAmount;
+        if (leftMakerAssetSpreadAmount > 0) {
+            // ERC20 Asset data itself is encoded as follows:
+            //
+            // | Area     | Offset | Length  | Contents                            |
+            // |----------|--------|---------|-------------------------------------|
+            // | Header   | 0      | 4       | function selector                   |
+            // | Params   |        | 1 * 32  | function parameters:                |
+            // |          | 4      | 12      |   1. token address padding          |
+            // |          | 16     | 20      |   2. token address                  |
+            bytes memory assetData = sellOrder.takerAssetData;
+            address token = assetData.readAddress(16);
+            // Calculate the excess from the buy order. This can occur if the buyer sends in a higher
+            // amount than the calculated current amount
+            uint256 buyerExcessAmount = safeSub(buyOrder.makerAssetAmount, auctionDetails.currentAmount);
+            uint256 sellerExcessAmount = safeSub(leftMakerAssetSpreadAmount, buyerExcessAmount);
+            // Return the difference between auctionDetails.currentAmount and sellOrder.takerAssetAmount
+            // to the seller
+            if (sellerExcessAmount > 0) {
+                IERC20Token(token).transfer(sellOrder.makerAddress, sellerExcessAmount);
+            }
+            // Return the difference between buyOrder.makerAssetAmount and auctionDetails.currentAmount
+            // to the buyer
+            if (buyerExcessAmount > 0) {
+                IERC20Token(token).transfer(buyOrder.makerAddress, buyerExcessAmount);
+            }
+        }
+        return matchedFillResults;
+    }
+
+    /// @dev Calculates the Auction Details for the given order
+    /// @param order The sell order
+    /// @return AuctionDetails
+    function getAuctionDetails(
+        LibOrder.Order memory order
+    )
+        public
+        returns (AuctionDetails memory auctionDetails)
+    {
+        uint256 makerAssetDataLength = order.makerAssetData.length;
+        // It is unknown the encoded data of makerAssetData, we assume the last 64 bytes
+        // are the Auction Details encoding.
+        // Auction Details is encoded as follows:
+        //
+        // | Area     | Offset | Length  | Contents                            |
+        // |----------|--------|---------|-------------------------------------|
+        // | Params   |        | 2 * 32  | parameters:                         |
+        // |          | -64    | 32      |   1. auction begin unix timestamp   |
+        // |          | -32    | 32      |   2. auction begin begin amount     |
+        // ERC20 asset data length is 4+32, 64 for auction details results in min length 100
+        require(
+            makerAssetDataLength >= 100,
+            "INVALID_ASSET_DATA"
+        );
+        uint256 auctionBeginTimeSeconds = order.makerAssetData.readUint256(makerAssetDataLength - 64);
+        uint256 auctionBeginAmount = order.makerAssetData.readUint256(makerAssetDataLength - 32);
+        // Ensure the auction has a valid begin time
+        require(
+            order.expirationTimeSeconds > auctionBeginTimeSeconds,
+            "INVALID_BEGIN_TIME"
+        );
+        uint256 auctionDurationSeconds = order.expirationTimeSeconds-auctionBeginTimeSeconds;
+        // Ensure the auction goes from high to low
+        uint256 minAmount = order.takerAssetAmount;
+        require(
+            auctionBeginAmount > minAmount,
+            "INVALID_AMOUNT"
+        );
+        uint256 amountDelta = auctionBeginAmount-minAmount;
+        // solhint-disable-next-line not-rely-on-time
+        uint256 timestamp = block.timestamp;
+        auctionDetails.beginTimeSeconds = auctionBeginTimeSeconds;
+        auctionDetails.endTimeSeconds = order.expirationTimeSeconds;
+        auctionDetails.beginAmount = auctionBeginAmount;
+        auctionDetails.endAmount = minAmount;
+        auctionDetails.currentTimeSeconds = timestamp;
+
+        uint256 remainingDurationSeconds = order.expirationTimeSeconds-timestamp;
+        if (timestamp < auctionBeginTimeSeconds) {
+            // If the auction has not yet begun the current amount is the auctionBeginAmount
+            auctionDetails.currentAmount = auctionBeginAmount;
+        } else if (timestamp >= order.expirationTimeSeconds) {
+            // If the auction has ended the current amount is the minAmount.
+            // Auction end time is guaranteed by 0x Exchange due to the order expiration
+            auctionDetails.currentAmount = minAmount;
+        } else {
+            auctionDetails.currentAmount = safeAdd(
+                minAmount,
+                safeDiv(
+                    safeMul(remainingDurationSeconds, amountDelta),
+                    auctionDurationSeconds
+                )
+            );
+        }
+        return auctionDetails;
+    }
+}
diff --git a/contracts/extensions/contracts/Forwarder/Forwarder.sol b/contracts/extensions/contracts/Forwarder/Forwarder.sol
new file mode 100644
index 000000000..94dec40ed
--- /dev/null
+++ b/contracts/extensions/contracts/Forwarder/Forwarder.sol
@@ -0,0 +1,50 @@
+/*
+
+  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 "./MixinWeth.sol";
+import "./MixinForwarderCore.sol";
+import "./libs/LibConstants.sol";
+import "./MixinAssets.sol";
+import "./MixinExchangeWrapper.sol";
+
+
+// solhint-disable no-empty-blocks
+contract Forwarder is
+    LibConstants,
+    MixinWeth,
+    MixinAssets,
+    MixinExchangeWrapper,
+    MixinForwarderCore
+{
+    constructor (
+        address _exchange,
+        bytes memory _zrxAssetData,
+        bytes memory _wethAssetData
+    )
+        public
+        LibConstants(
+            _exchange,
+            _zrxAssetData,
+            _wethAssetData
+        )
+        MixinForwarderCore()
+    {}
+}
diff --git a/contracts/extensions/contracts/Forwarder/MixinAssets.sol b/contracts/extensions/contracts/Forwarder/MixinAssets.sol
new file mode 100644
index 000000000..3ebf75161
--- /dev/null
+++ b/contracts/extensions/contracts/Forwarder/MixinAssets.sol
@@ -0,0 +1,143 @@
+/*
+
+  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 "./libs/LibConstants.sol";
+import "./mixins/MAssets.sol";
+
+
+contract MixinAssets is
+    Ownable,
+    LibConstants,
+    MAssets
+{
+    using LibBytes for bytes;
+
+    bytes4 constant internal ERC20_TRANSFER_SELECTOR = bytes4(keccak256("transfer(address,uint256)"));
+
+    /// @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 ERC20 token to withdraw.
+    function withdrawAsset(
+        bytes assetData,
+        uint256 amount
+    )
+        external
+        onlyOwner
+    {
+        transferAssetToSender(assetData, amount);
+    }
+
+    /// @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
+    {
+        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.
+        address token = assetData.readAddress(16);
+        uint256 tokenId = assetData.readUint256(36);
+
+        // Perform transfer.
+        IERC721Token(token).transferFrom(
+            address(this),
+            msg.sender,
+            tokenId
+        );
+    }
+}
diff --git a/contracts/extensions/contracts/Forwarder/MixinExchangeWrapper.sol b/contracts/extensions/contracts/Forwarder/MixinExchangeWrapper.sol
new file mode 100644
index 000000000..210eb14c2
--- /dev/null
+++ b/contracts/extensions/contracts/Forwarder/MixinExchangeWrapper.sol
@@ -0,0 +1,260 @@
+/*
+
+  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 "./mixins/MExchangeWrapper.sol";
+import "@0x/contracts-libs/contracts/libs/LibAbiEncoder.sol";
+import "@0x/contracts-libs/contracts/libs/LibOrder.sol";
+import "@0x/contracts-libs/contracts/libs/LibFillResults.sol";
+import "@0x/contracts-libs/contracts/libs/LibMath.sol";
+
+
+contract MixinExchangeWrapper is
+    LibAbiEncoder,
+    LibFillResults,
+    LibMath,
+    LibConstants,
+    MExchangeWrapper
+{
+    /// @dev Fills the input order.
+    ///      Returns false if the transaction would otherwise revert.
+    /// @param order Order struct containing order specifications.
+    /// @param takerAssetFillAmount Desired amount of takerAsset to sell.
+    /// @param signature Proof that order has been created by maker.
+    /// @return Amounts filled and fees paid by maker and taker.
+    function fillOrderNoThrow(
+        LibOrder.Order memory order,
+        uint256 takerAssetFillAmount,
+        bytes memory signature
+    )
+        internal
+        returns (FillResults memory fillResults)
+    {
+        // ABI encode calldata for `fillOrder`
+        bytes memory fillOrderCalldata = abiEncodeFillOrder(
+            order,
+            takerAssetFillAmount,
+            signature
+        );
+
+        address exchange = address(EXCHANGE);
+
+        // Call `fillOrder` and handle any exceptions gracefully
+        assembly {
+            let success := call(
+                gas,                                // forward all gas
+                exchange,                           // call address of Exchange contract
+                0,                                  // transfer 0 wei
+                add(fillOrderCalldata, 32),         // pointer to start of input (skip array length in first 32 bytes)
+                mload(fillOrderCalldata),           // length of input
+                fillOrderCalldata,                  // write output over input
+                128                                 // output size is 128 bytes
+            )
+            if success {
+                mstore(fillResults, mload(fillOrderCalldata))
+                mstore(add(fillResults, 32), mload(add(fillOrderCalldata, 32)))
+                mstore(add(fillResults, 64), mload(add(fillOrderCalldata, 64)))
+                mstore(add(fillResults, 96), mload(add(fillOrderCalldata, 96)))
+            }
+        }
+        // fillResults values will be 0 by default if call was unsuccessful
+        return fillResults;
+    }
+
+    /// @dev Synchronously executes multiple calls of fillOrder until total amount of WETH has been sold by taker.
+    ///      Returns false if the transaction would otherwise revert.
+    /// @param orders Array of order specifications.
+    /// @param wethSellAmount Desired amount of WETH to sell.
+    /// @param signatures Proofs that orders have been signed by makers.
+    /// @return Amounts filled and fees paid by makers and taker.
+    function marketSellWeth(
+        LibOrder.Order[] memory orders,
+        uint256 wethSellAmount,
+        bytes[] memory signatures
+    )
+        internal
+        returns (FillResults memory totalFillResults)
+    {
+        bytes memory makerAssetData = orders[0].makerAssetData;
+        bytes memory wethAssetData = WETH_ASSET_DATA;
+
+        uint256 ordersLength = orders.length;
+        for (uint256 i = 0; i != ordersLength; i++) {
+
+            // We assume that asset being bought by taker is the same for each order.
+            // We assume that asset being sold by taker is WETH for each order.
+            orders[i].makerAssetData = makerAssetData;
+            orders[i].takerAssetData = wethAssetData;
+
+            // Calculate the remaining amount of WETH to sell
+            uint256 remainingTakerAssetFillAmount = safeSub(wethSellAmount, totalFillResults.takerAssetFilledAmount);
+
+            // Attempt to sell the remaining amount of WETH
+            FillResults memory singleFillResults = fillOrderNoThrow(
+                orders[i],
+                remainingTakerAssetFillAmount,
+                signatures[i]
+            );
+
+            // Update amounts filled and fees paid by maker and taker
+            addFillResults(totalFillResults, singleFillResults);
+
+            // Stop execution if the entire amount of takerAsset has been sold
+            if (totalFillResults.takerAssetFilledAmount >= wethSellAmount) {
+                break;
+            }
+        }
+        return totalFillResults;
+    }
+
+    /// @dev Synchronously executes multiple fill orders in a single transaction until total amount is bought by taker.
+    ///      Returns false if the transaction would otherwise revert.
+    ///      The asset being sold by taker must always be WETH.
+    /// @param orders Array of order specifications.
+    /// @param makerAssetFillAmount Desired amount of makerAsset to buy.
+    /// @param signatures Proofs that orders have been signed by makers.
+    /// @return Amounts filled and fees paid by makers and taker.
+    function marketBuyExactAmountWithWeth(
+        LibOrder.Order[] memory orders,
+        uint256 makerAssetFillAmount,
+        bytes[] memory signatures
+    )
+        internal
+        returns (FillResults memory totalFillResults)
+    {
+        bytes memory makerAssetData = orders[0].makerAssetData;
+        bytes memory wethAssetData = WETH_ASSET_DATA;
+
+        uint256 ordersLength = orders.length;
+        for (uint256 i = 0; i != ordersLength; i++) {
+
+            // We assume that asset being bought by taker is the same for each order.
+            // We assume that asset being sold by taker is WETH for each order.
+            orders[i].makerAssetData = makerAssetData;
+            orders[i].takerAssetData = wethAssetData;
+
+            // Calculate the remaining amount of makerAsset to buy
+            uint256 remainingMakerAssetFillAmount = safeSub(makerAssetFillAmount, totalFillResults.makerAssetFilledAmount);
+
+            // Convert the remaining amount of makerAsset to buy into remaining amount
+            // of takerAsset to sell, assuming entire amount can be sold in the current order.
+            // We round up because the exchange rate computed by fillOrder rounds in favor
+            // of the Maker. In this case we want to overestimate the amount of takerAsset.
+            uint256 remainingTakerAssetFillAmount = getPartialAmountCeil(
+                orders[i].takerAssetAmount,
+                orders[i].makerAssetAmount,
+                remainingMakerAssetFillAmount
+            );
+
+            // Attempt to sell the remaining amount of takerAsset
+            FillResults memory singleFillResults = fillOrderNoThrow(
+                orders[i],
+                remainingTakerAssetFillAmount,
+                signatures[i]
+            );
+
+            // Update amounts filled and fees paid by maker and taker
+            addFillResults(totalFillResults, singleFillResults);
+
+            // Stop execution if the entire amount of makerAsset has been bought
+            uint256 makerAssetFilledAmount = totalFillResults.makerAssetFilledAmount;
+            if (makerAssetFilledAmount >= makerAssetFillAmount) {
+                break;
+            }
+        }
+
+        require(
+            makerAssetFilledAmount >= makerAssetFillAmount,
+            "COMPLETE_FILL_FAILED"
+        );
+        return totalFillResults;
+    }
+
+    /// @dev Buys zrxBuyAmount of ZRX fee tokens, taking into account ZRX fees for each order. This will guarantee
+    ///      that at least zrxBuyAmount of ZRX is purchased (sometimes slightly over due to rounding issues).
+    ///      It is possible that a request to buy 200 ZRX will require purchasing 202 ZRX
+    ///      as 2 ZRX is required to purchase the 200 ZRX fee tokens. This guarantees at least 200 ZRX for future purchases.
+    ///      The asset being sold by taker must always be WETH. 
+    /// @param orders Array of order specifications containing ZRX as makerAsset and WETH as takerAsset.
+    /// @param zrxBuyAmount Desired amount of ZRX to buy.
+    /// @param signatures Proofs that orders have been created by makers.
+    /// @return totalFillResults Amounts filled and fees paid by maker and taker.
+    function marketBuyExactZrxWithWeth(
+        LibOrder.Order[] memory orders,
+        uint256 zrxBuyAmount,
+        bytes[] memory signatures
+    )
+        internal
+        returns (FillResults memory totalFillResults)
+    {
+        // Do nothing if zrxBuyAmount == 0
+        if (zrxBuyAmount == 0) {
+            return totalFillResults;
+        }
+
+        bytes memory zrxAssetData = ZRX_ASSET_DATA;
+        bytes memory wethAssetData = WETH_ASSET_DATA;
+        uint256 zrxPurchased = 0;
+
+        uint256 ordersLength = orders.length;
+        for (uint256 i = 0; i != ordersLength; i++) {
+
+            // All of these are ZRX/WETH, so we can drop the respective assetData from calldata.
+            orders[i].makerAssetData = zrxAssetData;
+            orders[i].takerAssetData = wethAssetData;
+
+            // Calculate the remaining amount of ZRX to buy.
+            uint256 remainingZrxBuyAmount = safeSub(zrxBuyAmount, zrxPurchased);
+
+            // Convert the remaining amount of ZRX to buy into remaining amount
+            // of WETH to sell, assuming entire amount can be sold in the current order.
+            // We round up because the exchange rate computed by fillOrder rounds in favor
+            // of the Maker. In this case we want to overestimate the amount of takerAsset.
+            uint256 remainingWethSellAmount = getPartialAmountCeil(
+                orders[i].takerAssetAmount,
+                safeSub(orders[i].makerAssetAmount, orders[i].takerFee),  // our exchange rate after fees 
+                remainingZrxBuyAmount
+            );
+
+            // Attempt to sell the remaining amount of WETH.
+            FillResults memory singleFillResult = fillOrderNoThrow(
+                orders[i],
+                remainingWethSellAmount,
+                signatures[i]
+            );
+
+            // Update amounts filled and fees paid by maker and taker.
+            addFillResults(totalFillResults, singleFillResult);
+            zrxPurchased = safeSub(totalFillResults.makerAssetFilledAmount, totalFillResults.takerFeePaid);
+
+            // Stop execution if the entire amount of ZRX has been bought.
+            if (zrxPurchased >= zrxBuyAmount) {
+                break;
+            }
+        }
+
+        require(
+            zrxPurchased >= zrxBuyAmount,
+            "COMPLETE_FILL_FAILED"
+        );
+        return totalFillResults;
+    }
+}
diff --git a/contracts/extensions/contracts/Forwarder/MixinForwarderCore.sol b/contracts/extensions/contracts/Forwarder/MixinForwarderCore.sol
new file mode 100644
index 000000000..bab78d79b
--- /dev/null
+++ b/contracts/extensions/contracts/Forwarder/MixinForwarderCore.sol
@@ -0,0 +1,214 @@
+/*
+
+  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 "./mixins/MWeth.sol";
+import "./mixins/MAssets.sol";
+import "./mixins/MExchangeWrapper.sol";
+import "./interfaces/IForwarderCore.sol";
+import "@0x/contracts-utils/contracts/utils/LibBytes/LibBytes.sol";
+import "@0x/contracts-libs/contracts/libs/LibOrder.sol";
+import "@0x/contracts-libs/contracts/libs/LibFillResults.sol";
+import "@0x/contracts-libs/contracts/libs/LibMath.sol";
+
+
+contract MixinForwarderCore is
+    LibFillResults,
+    LibMath,
+    LibConstants,
+    MWeth,
+    MAssets,
+    MExchangeWrapper,
+    IForwarderCore
+{
+    using LibBytes for bytes;
+
+    /// @dev Constructor approves ERC20 proxy to transfer ZRX and WETH on this contract's behalf.
+    constructor ()
+        public
+    {
+        address proxyAddress = EXCHANGE.getAssetProxy(ERC20_DATA_ID);
+        require(
+            proxyAddress != address(0),
+            "UNREGISTERED_ASSET_PROXY"
+        );
+        ETHER_TOKEN.approve(proxyAddress, MAX_UINT);
+        ZRX_TOKEN.approve(proxyAddress, MAX_UINT);
+    }
+
+    /// @dev Purchases as much of orders' makerAssets as possible by selling up to 95% of transaction's ETH value.
+    ///      Any ZRX required to pay fees for primary orders will automatically be purchased by this contract.
+    ///      5% of ETH value is reserved for paying fees to order feeRecipients (in ZRX) and forwarding contract feeRecipient (in ETH).
+    ///      Any ETH not spent will be refunded to sender.
+    /// @param orders Array of order specifications used containing desired makerAsset and WETH as takerAsset. 
+    /// @param signatures Proofs that orders have been created by makers.
+    /// @param feeOrders Array of order specifications containing ZRX as makerAsset and WETH as takerAsset. Used to purchase ZRX for primary order fees.
+    /// @param feeSignatures Proofs that feeOrders have been created by makers.
+    /// @param feePercentage Percentage of WETH sold that will payed as fee to forwarding contract feeRecipient.
+    /// @param feeRecipient Address that will receive ETH when orders are filled.
+    /// @return Amounts filled and fees paid by maker and taker for both sets of orders.
+    function marketSellOrdersWithEth(
+        LibOrder.Order[] memory orders,
+        bytes[] memory signatures,
+        LibOrder.Order[] memory feeOrders,
+        bytes[] memory feeSignatures,
+        uint256  feePercentage,
+        address feeRecipient
+    )
+        public
+        payable
+        returns (
+            FillResults memory orderFillResults,
+            FillResults memory feeOrderFillResults
+        )
+    {
+        // Convert ETH to WETH.
+        convertEthToWeth();
+
+        uint256 wethSellAmount;
+        uint256 zrxBuyAmount;
+        uint256 makerAssetAmountPurchased;
+        if (orders[0].makerAssetData.equals(ZRX_ASSET_DATA)) {
+            // Calculate amount of WETH that won't be spent on ETH fees.
+            wethSellAmount = getPartialAmountFloor(
+                PERCENTAGE_DENOMINATOR,
+                safeAdd(PERCENTAGE_DENOMINATOR, feePercentage),
+                msg.value
+            );
+            // Market sell available WETH.
+            // ZRX fees are paid with this contract's balance.
+            orderFillResults = marketSellWeth(
+                orders,
+                wethSellAmount,
+                signatures
+            );
+            // The fee amount must be deducted from the amount transfered back to sender.
+            makerAssetAmountPurchased = safeSub(orderFillResults.makerAssetFilledAmount, orderFillResults.takerFeePaid);
+        } else {
+            // 5% of WETH is reserved for filling feeOrders and paying feeRecipient.
+            wethSellAmount = getPartialAmountFloor(
+                MAX_WETH_FILL_PERCENTAGE,
+                PERCENTAGE_DENOMINATOR,
+                msg.value
+            );
+            // Market sell 95% of WETH.
+            // ZRX fees are payed with this contract's balance.
+            orderFillResults = marketSellWeth(
+                orders,
+                wethSellAmount,
+                signatures
+            );
+            // Buy back all ZRX spent on fees.
+            zrxBuyAmount = orderFillResults.takerFeePaid;
+            feeOrderFillResults = marketBuyExactZrxWithWeth(
+                feeOrders,
+                zrxBuyAmount,
+                feeSignatures
+            );
+            makerAssetAmountPurchased = orderFillResults.makerAssetFilledAmount;
+        }
+
+        // Transfer feePercentage of total ETH spent on primary orders to feeRecipient.
+        // Refund remaining ETH to msg.sender.
+        transferEthFeeAndRefund(
+            orderFillResults.takerAssetFilledAmount,
+            feeOrderFillResults.takerAssetFilledAmount,
+            feePercentage,
+            feeRecipient
+        );
+
+        // Transfer purchased assets to msg.sender.
+        transferAssetToSender(orders[0].makerAssetData, makerAssetAmountPurchased);
+    }
+
+    /// @dev Attempt to purchase makerAssetFillAmount of makerAsset by selling ETH provided with transaction.
+    ///      Any ZRX required to pay fees for primary orders will automatically be purchased by this contract.
+    ///      Any ETH not spent will be refunded to sender.
+    /// @param orders Array of order specifications used containing desired makerAsset and WETH as takerAsset. 
+    /// @param makerAssetFillAmount Desired amount of makerAsset to purchase.
+    /// @param signatures Proofs that orders have been created by makers.
+    /// @param feeOrders Array of order specifications containing ZRX as makerAsset and WETH as takerAsset. Used to purchase ZRX for primary order fees.
+    /// @param feeSignatures Proofs that feeOrders have been created by makers.
+    /// @param feePercentage Percentage of WETH sold that will payed as fee to forwarding contract feeRecipient.
+    /// @param feeRecipient Address that will receive ETH when orders are filled.
+    /// @return Amounts filled and fees paid by maker and taker for both sets of orders.
+    function marketBuyOrdersWithEth(
+        LibOrder.Order[] memory orders,
+        uint256 makerAssetFillAmount,
+        bytes[] memory signatures,
+        LibOrder.Order[] memory feeOrders,
+        bytes[] memory feeSignatures,
+        uint256  feePercentage,
+        address feeRecipient
+    )
+        public
+        payable
+        returns (
+            FillResults memory orderFillResults,
+            FillResults memory feeOrderFillResults
+        )
+    {
+        // Convert ETH to WETH.
+        convertEthToWeth();
+
+        uint256 zrxBuyAmount;
+        uint256 makerAssetAmountPurchased;
+        if (orders[0].makerAssetData.equals(ZRX_ASSET_DATA)) {
+            // If the makerAsset is ZRX, it is not necessary to pay fees out of this
+            // contracts's ZRX balance because fees are factored into the price of the order.
+            orderFillResults = marketBuyExactZrxWithWeth(
+                orders,
+                makerAssetFillAmount,
+                signatures
+            );
+            // The fee amount must be deducted from the amount transfered back to sender.
+            makerAssetAmountPurchased = safeSub(orderFillResults.makerAssetFilledAmount, orderFillResults.takerFeePaid);
+        } else {
+            // Attemp to purchase desired amount of makerAsset.
+            // ZRX fees are payed with this contract's balance.
+            orderFillResults = marketBuyExactAmountWithWeth(
+                orders,
+                makerAssetFillAmount,
+                signatures
+            );
+            // Buy back all ZRX spent on fees.
+            zrxBuyAmount = orderFillResults.takerFeePaid;
+            feeOrderFillResults = marketBuyExactZrxWithWeth(
+                feeOrders,
+                zrxBuyAmount,
+                feeSignatures
+            );
+            makerAssetAmountPurchased = orderFillResults.makerAssetFilledAmount;
+        }
+
+        // Transfer feePercentage of total ETH spent on primary orders to feeRecipient.
+        // Refund remaining ETH to msg.sender.
+        transferEthFeeAndRefund(
+            orderFillResults.takerAssetFilledAmount,
+            feeOrderFillResults.takerAssetFilledAmount,
+            feePercentage,
+            feeRecipient
+        );
+
+        // Transfer purchased assets to msg.sender.
+        transferAssetToSender(orders[0].makerAssetData, makerAssetAmountPurchased);
+    }
+}
diff --git a/contracts/extensions/contracts/Forwarder/MixinWeth.sol b/contracts/extensions/contracts/Forwarder/MixinWeth.sol
new file mode 100644
index 000000000..2a281f3ae
--- /dev/null
+++ b/contracts/extensions/contracts/Forwarder/MixinWeth.sol
@@ -0,0 +1,113 @@
+/*
+
+  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-libs/contracts/libs/LibMath.sol";
+import "./libs/LibConstants.sol";
+import "./mixins/MWeth.sol";
+
+
+contract MixinWeth is
+    LibMath,
+    LibConstants,
+    MWeth
+{
+    /// @dev Default payabale function, this allows us to withdraw WETH
+    function ()
+        public
+        payable
+    {
+        require(
+            msg.sender == address(ETHER_TOKEN),
+            "DEFAULT_FUNCTION_WETH_CONTRACT_ONLY"
+        );
+    }
+
+    /// @dev Converts message call's ETH value into WETH.
+    function convertEthToWeth()
+        internal
+    {
+        require(
+            msg.value > 0,
+            "INVALID_MSG_VALUE"
+        );
+        ETHER_TOKEN.deposit.value(msg.value)();
+    }
+
+    /// @dev Transfers feePercentage of WETH spent on primary orders to feeRecipient.
+    ///      Refunds any excess ETH to msg.sender.
+    /// @param wethSoldExcludingFeeOrders Amount of WETH sold when filling primary orders.
+    /// @param wethSoldForZrx Amount of WETH sold when purchasing ZRX required for primary order fees.
+    /// @param feePercentage Percentage of WETH sold that will payed as fee to forwarding contract feeRecipient.
+    /// @param feeRecipient Address that will receive ETH when orders are filled.
+    function transferEthFeeAndRefund(
+        uint256 wethSoldExcludingFeeOrders,
+        uint256 wethSoldForZrx,
+        uint256 feePercentage,
+        address feeRecipient
+    )
+        internal
+    {
+        // Ensure feePercentage is less than 5%.
+        require(
+            feePercentage <= MAX_FEE_PERCENTAGE,
+            "FEE_PERCENTAGE_TOO_LARGE"
+        );
+
+        // Ensure that no extra WETH owned by this contract has been sold.
+        uint256 wethSold = safeAdd(wethSoldExcludingFeeOrders, wethSoldForZrx);
+        require(
+            wethSold <= msg.value,
+            "OVERSOLD_WETH"
+        );
+
+        // Calculate amount of WETH that hasn't been sold.
+        uint256 wethRemaining = safeSub(msg.value, wethSold);
+
+        // Calculate ETH fee to pay to feeRecipient.
+        uint256 ethFee = getPartialAmountFloor(
+            feePercentage,
+            PERCENTAGE_DENOMINATOR,
+            wethSoldExcludingFeeOrders
+        );
+
+        // Ensure fee is less than amount of WETH remaining.
+        require(
+            ethFee <= wethRemaining,
+            "INSUFFICIENT_ETH_REMAINING"
+        );
+    
+        // Do nothing if no WETH remaining
+        if (wethRemaining > 0) {
+            // Convert remaining WETH to ETH
+            ETHER_TOKEN.withdraw(wethRemaining);
+
+            // Pay ETH to feeRecipient
+            if (ethFee > 0) {
+                feeRecipient.transfer(ethFee);
+            }
+
+            // Refund remaining ETH to msg.sender.
+            uint256 ethRefund = safeSub(wethRemaining, ethFee);
+            if (ethRefund > 0) {
+                msg.sender.transfer(ethRefund);
+            }
+        }
+    }
+}
diff --git a/contracts/extensions/contracts/Forwarder/interfaces/IAssets.sol b/contracts/extensions/contracts/Forwarder/interfaces/IAssets.sol
new file mode 100644
index 000000000..1e034c003
--- /dev/null
+++ b/contracts/extensions/contracts/Forwarder/interfaces/IAssets.sol
@@ -0,0 +1,34 @@
+/*
+
+  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 ERC20 token to withdraw.
+    function withdrawAsset(
+        bytes assetData,
+        uint256 amount
+    )
+        external;
+}
diff --git a/contracts/extensions/contracts/Forwarder/interfaces/IForwarder.sol b/contracts/extensions/contracts/Forwarder/interfaces/IForwarder.sol
new file mode 100644
index 000000000..f5a26e2ba
--- /dev/null
+++ b/contracts/extensions/contracts/Forwarder/interfaces/IForwarder.sol
@@ -0,0 +1,30 @@
+/*
+
+  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 "./IForwarderCore.sol";
+import "./IAssets.sol";
+
+
+// solhint-disable no-empty-blocks
+contract IForwarder is
+    IForwarderCore,
+    IAssets
+{}
diff --git a/contracts/extensions/contracts/Forwarder/interfaces/IForwarderCore.sol b/contracts/extensions/contracts/Forwarder/interfaces/IForwarderCore.sol
new file mode 100644
index 000000000..eede20bb8
--- /dev/null
+++ b/contracts/extensions/contracts/Forwarder/interfaces/IForwarderCore.sol
@@ -0,0 +1,80 @@
+/*
+
+  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";
+import "@0x/contracts-libs/contracts/libs/LibFillResults.sol";
+
+
+contract IForwarderCore {
+
+    /// @dev Purchases as much of orders' makerAssets as possible by selling up to 95% of transaction's ETH value.
+    ///      Any ZRX required to pay fees for primary orders will automatically be purchased by this contract.
+    ///      5% of ETH value is reserved for paying fees to order feeRecipients (in ZRX) and forwarding contract feeRecipient (in ETH).
+    ///      Any ETH not spent will be refunded to sender.
+    /// @param orders Array of order specifications used containing desired makerAsset and WETH as takerAsset. 
+    /// @param signatures Proofs that orders have been created by makers.
+    /// @param feeOrders Array of order specifications containing ZRX as makerAsset and WETH as takerAsset. Used to purchase ZRX for primary order fees.
+    /// @param feeSignatures Proofs that feeOrders have been created by makers.
+    /// @param feePercentage Percentage of WETH sold that will payed as fee to forwarding contract feeRecipient.
+    /// @param feeRecipient Address that will receive ETH when orders are filled.
+    /// @return Amounts filled and fees paid by maker and taker for both sets of orders.
+    function marketSellOrdersWithEth(
+        LibOrder.Order[] memory orders,
+        bytes[] memory signatures,
+        LibOrder.Order[] memory feeOrders,
+        bytes[] memory feeSignatures,
+        uint256  feePercentage,
+        address feeRecipient
+    )
+        public
+        payable
+        returns (
+            LibFillResults.FillResults memory orderFillResults,
+            LibFillResults.FillResults memory feeOrderFillResults
+        );
+
+    /// @dev Attempt to purchase makerAssetFillAmount of makerAsset by selling ETH provided with transaction.
+    ///      Any ZRX required to pay fees for primary orders will automatically be purchased by this contract.
+    ///      Any ETH not spent will be refunded to sender.
+    /// @param orders Array of order specifications used containing desired makerAsset and WETH as takerAsset. 
+    /// @param makerAssetFillAmount Desired amount of makerAsset to purchase.
+    /// @param signatures Proofs that orders have been created by makers.
+    /// @param feeOrders Array of order specifications containing ZRX as makerAsset and WETH as takerAsset. Used to purchase ZRX for primary order fees.
+    /// @param feeSignatures Proofs that feeOrders have been created by makers.
+    /// @param feePercentage Percentage of WETH sold that will payed as fee to forwarding contract feeRecipient.
+    /// @param feeRecipient Address that will receive ETH when orders are filled.
+    /// @return Amounts filled and fees paid by maker and taker for both sets of orders.
+    function marketBuyOrdersWithEth(
+        LibOrder.Order[] memory orders,
+        uint256 makerAssetFillAmount,
+        bytes[] memory signatures,
+        LibOrder.Order[] memory feeOrders,
+        bytes[] memory feeSignatures,
+        uint256  feePercentage,
+        address feeRecipient
+    )
+        public
+        payable
+        returns (
+            LibFillResults.FillResults memory orderFillResults,
+            LibFillResults.FillResults memory feeOrderFillResults
+        );
+}
diff --git a/contracts/extensions/contracts/Forwarder/libs/LibConstants.sol b/contracts/extensions/contracts/Forwarder/libs/LibConstants.sol
new file mode 100644
index 000000000..4a81abf76
--- /dev/null
+++ b/contracts/extensions/contracts/Forwarder/libs/LibConstants.sol
@@ -0,0 +1,62 @@
+/*
+
+  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-interfaces/contracts/protocol/Exchange/IExchange.sol";
+import "@0x/contracts-tokens/contracts/tokens/EtherToken/IEtherToken.sol";
+import "@0x/contracts-tokens/contracts/tokens/ERC20Token/IERC20Token.sol";
+
+
+contract LibConstants {
+
+    using LibBytes for bytes;
+
+    bytes4 constant internal ERC20_DATA_ID = bytes4(keccak256("ERC20Token(address)"));
+    bytes4 constant internal ERC721_DATA_ID = bytes4(keccak256("ERC721Token(address,uint256)"));
+    uint256 constant internal MAX_UINT = 2**256 - 1;
+    uint256 constant internal PERCENTAGE_DENOMINATOR = 10**18; 
+    uint256 constant internal MAX_FEE_PERCENTAGE = 5 * PERCENTAGE_DENOMINATOR / 100;         // 5%
+    uint256 constant internal MAX_WETH_FILL_PERCENTAGE = 95 * PERCENTAGE_DENOMINATOR / 100;  // 95%
+ 
+     // solhint-disable var-name-mixedcase
+    IExchange internal EXCHANGE;
+    IEtherToken internal ETHER_TOKEN;
+    IERC20Token internal ZRX_TOKEN;
+    bytes internal ZRX_ASSET_DATA;
+    bytes internal WETH_ASSET_DATA;
+    // solhint-enable var-name-mixedcase
+
+    constructor (
+        address _exchange,
+        bytes memory _zrxAssetData,
+        bytes memory _wethAssetData
+    )
+        public
+    {
+        EXCHANGE = IExchange(_exchange);
+        ZRX_ASSET_DATA = _zrxAssetData;
+        WETH_ASSET_DATA = _wethAssetData;
+
+        address etherToken = _wethAssetData.readAddress(16);
+        address zrxToken = _zrxAssetData.readAddress(16);
+        ETHER_TOKEN = IEtherToken(etherToken);
+        ZRX_TOKEN = IERC20Token(zrxToken);
+    }
+}
diff --git a/contracts/extensions/contracts/Forwarder/libs/LibForwarderErrors.sol b/contracts/extensions/contracts/Forwarder/libs/LibForwarderErrors.sol
new file mode 100644
index 000000000..fb3ade1db
--- /dev/null
+++ b/contracts/extensions/contracts/Forwarder/libs/LibForwarderErrors.sol
@@ -0,0 +1,34 @@
+/*
+
+  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.
+
+*/
+
+// solhint-disable
+pragma solidity 0.4.24;
+
+
+/// This contract is intended to serve as a reference, but is not actually used for efficiency reasons.
+contract LibForwarderErrors {
+    string constant FEE_PERCENTAGE_TOO_LARGE = "FEE_PROPORTION_TOO_LARGE";                        // Provided fee percentage greater than 5%.
+    string constant INSUFFICIENT_ETH_REMAINING = "INSUFFICIENT_ETH_REMAINING";                    // Not enough ETH remaining to pay feeRecipient.
+    string constant OVERSOLD_WETH = "OVERSOLD_WETH";                                              // More WETH sold than provided with current message call.
+    string constant COMPLETE_FILL_FAILED = "COMPLETE_FILL_FAILED";                                // Desired purchase amount not completely filled (required for ZRX fees only).
+    string constant TRANSFER_FAILED = "TRANSFER_FAILED";                                          // Asset transfer failed.
+    string constant UNSUPPORTED_ASSET_PROXY = "UNSUPPORTED_ASSET_PROXY";                          // Proxy in assetData not supported.
+    string constant DEFAULT_FUNCTION_WETH_CONTRACT_ONLY = "DEFAULT_FUNCTION_WETH_CONTRACT_ONLY";  // Fallback function may only be used for WETH withdrawals.
+    string constant INVALID_MSG_VALUE = "INVALID_MSG_VALUE";                                      // msg.value must be greater than 0.
+    string constant INVALID_AMOUNT = "INVALID_AMOUNT";                                            // Amount must equal 1.
+}
diff --git a/contracts/extensions/contracts/Forwarder/mixins/MAssets.sol b/contracts/extensions/contracts/Forwarder/mixins/MAssets.sol
new file mode 100644
index 000000000..9e7f80d97
--- /dev/null
+++ b/contracts/extensions/contracts/Forwarder/mixins/MAssets.sol
@@ -0,0 +1,53 @@
+/*
+
+  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;
+}
diff --git a/contracts/extensions/contracts/Forwarder/mixins/MExchangeWrapper.sol b/contracts/extensions/contracts/Forwarder/mixins/MExchangeWrapper.sol
new file mode 100644
index 000000000..d9e71786a
--- /dev/null
+++ b/contracts/extensions/contracts/Forwarder/mixins/MExchangeWrapper.sol
@@ -0,0 +1,87 @@
+/*
+
+  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";
+import "@0x/contracts-libs/contracts/libs/LibFillResults.sol";
+
+
+contract MExchangeWrapper {
+
+    /// @dev Fills the input order.
+    ///      Returns false if the transaction would otherwise revert.
+    /// @param order Order struct containing order specifications.
+    /// @param takerAssetFillAmount Desired amount of takerAsset to sell.
+    /// @param signature Proof that order has been created by maker.
+    /// @return Amounts filled and fees paid by maker and taker.
+    function fillOrderNoThrow(
+        LibOrder.Order memory order,
+        uint256 takerAssetFillAmount,
+        bytes memory signature
+    )
+        internal
+        returns (LibFillResults.FillResults memory fillResults);
+
+    /// @dev Synchronously executes multiple calls of fillOrder until total amount of WETH has been sold by taker.
+    ///      Returns false if the transaction would otherwise revert.
+    /// @param orders Array of order specifications.
+    /// @param wethSellAmount Desired amount of WETH to sell.
+    /// @param signatures Proofs that orders have been signed by makers.
+    /// @return Amounts filled and fees paid by makers and taker.
+    function marketSellWeth(
+        LibOrder.Order[] memory orders,
+        uint256 wethSellAmount,
+        bytes[] memory signatures
+    )
+        internal
+        returns (LibFillResults.FillResults memory totalFillResults);
+
+    /// @dev Synchronously executes multiple fill orders in a single transaction until total amount is bought by taker.
+    ///      Returns false if the transaction would otherwise revert.
+    ///      The asset being sold by taker must always be WETH.
+    /// @param orders Array of order specifications.
+    /// @param makerAssetFillAmount Desired amount of makerAsset to buy.
+    /// @param signatures Proofs that orders have been signed by makers.
+    /// @return Amounts filled and fees paid by makers and taker.
+    function marketBuyExactAmountWithWeth(
+        LibOrder.Order[] memory orders,
+        uint256 makerAssetFillAmount,
+        bytes[] memory signatures
+    )
+        internal
+        returns (LibFillResults.FillResults memory totalFillResults);
+
+    /// @dev Buys zrxBuyAmount of ZRX fee tokens, taking into account ZRX fees for each order. This will guarantee
+    ///      that at least zrxBuyAmount of ZRX is purchased (sometimes slightly over due to rounding issues).
+    ///      It is possible that a request to buy 200 ZRX will require purchasing 202 ZRX
+    ///      as 2 ZRX is required to purchase the 200 ZRX fee tokens. This guarantees at least 200 ZRX for future purchases.
+    ///      The asset being sold by taker must always be WETH. 
+    /// @param orders Array of order specifications containing ZRX as makerAsset and WETH as takerAsset.
+    /// @param zrxBuyAmount Desired amount of ZRX to buy.
+    /// @param signatures Proofs that orders have been created by makers.
+    /// @return totalFillResults Amounts filled and fees paid by maker and taker.
+    function marketBuyExactZrxWithWeth(
+        LibOrder.Order[] memory orders,
+        uint256 zrxBuyAmount,
+        bytes[] memory signatures
+    )
+        internal
+        returns (LibFillResults.FillResults memory totalFillResults);
+}
diff --git a/contracts/extensions/contracts/Forwarder/mixins/MWeth.sol b/contracts/extensions/contracts/Forwarder/mixins/MWeth.sol
new file mode 100644
index 000000000..88e77be4e
--- /dev/null
+++ b/contracts/extensions/contracts/Forwarder/mixins/MWeth.sol
@@ -0,0 +1,41 @@
+/*
+
+  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 MWeth {
+
+    /// @dev Converts message call's ETH value into WETH.
+    function convertEthToWeth()
+        internal;
+
+    /// @dev Transfers feePercentage of WETH spent on primary orders to feeRecipient.
+    ///      Refunds any excess ETH to msg.sender.
+    /// @param wethSoldExcludingFeeOrders Amount of WETH sold when filling primary orders.
+    /// @param wethSoldForZrx Amount of WETH sold when purchasing ZRX required for primary order fees.
+    /// @param feePercentage Percentage of WETH sold that will payed as fee to forwarding contract feeRecipient.
+    /// @param feeRecipient Address that will receive ETH when orders are filled.
+    function transferEthFeeAndRefund(
+        uint256 wethSoldExcludingFeeOrders,
+        uint256 wethSoldForZrx,
+        uint256 feePercentage,
+        address feeRecipient
+    )
+        internal;
+}
diff --git a/contracts/extensions/contracts/OrderValidator/OrderValidator.sol b/contracts/extensions/contracts/OrderValidator/OrderValidator.sol
new file mode 100644
index 000000000..33dd1326c
--- /dev/null
+++ b/contracts/extensions/contracts/OrderValidator/OrderValidator.sol
@@ -0,0 +1,218 @@
+/*
+
+  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-interfaces/contracts/protocol/Exchange/IExchange.sol";
+import "@0x/contracts-libs/contracts/libs/LibOrder.sol";
+import "@0x/contracts-tokens/contracts/tokens/ERC20Token/IERC20Token.sol";
+import "@0x/contracts-tokens/contracts/tokens/ERC721Token/IERC721Token.sol";
+import "@0x/contracts-utils/contracts/utils/LibBytes/LibBytes.sol";
+
+
+contract OrderValidator {
+
+    using LibBytes for bytes;
+
+    bytes4 constant internal ERC20_DATA_ID = bytes4(keccak256("ERC20Token(address)"));
+    bytes4 constant internal ERC721_DATA_ID = bytes4(keccak256("ERC721Token(address,uint256)"));
+
+    struct TraderInfo {
+        uint256 makerBalance;       // Maker's balance of makerAsset
+        uint256 makerAllowance;     // Maker's allowance to corresponding AssetProxy
+        uint256 takerBalance;       // Taker's balance of takerAsset
+        uint256 takerAllowance;     // Taker's allowance to corresponding AssetProxy
+        uint256 makerZrxBalance;    // Maker's balance of ZRX
+        uint256 makerZrxAllowance;  // Maker's allowance of ZRX to ERC20Proxy
+        uint256 takerZrxBalance;    // Taker's balance of ZRX
+        uint256 takerZrxAllowance;  // Taker's allowance of ZRX to ERC20Proxy
+    }
+
+    // solhint-disable var-name-mixedcase
+    IExchange internal EXCHANGE;
+    bytes internal ZRX_ASSET_DATA;
+    // solhint-enable var-name-mixedcase
+
+    constructor (address _exchange, bytes memory _zrxAssetData)
+        public
+    {
+        EXCHANGE = IExchange(_exchange);
+        ZRX_ASSET_DATA = _zrxAssetData;
+    }
+
+    /// @dev Fetches information for order and maker/taker of order.
+    /// @param order The order structure.
+    /// @param takerAddress Address that will be filling the order.
+    /// @return OrderInfo and TraderInfo instances for given order.
+    function getOrderAndTraderInfo(LibOrder.Order memory order, address takerAddress)
+        public
+        view
+        returns (LibOrder.OrderInfo memory orderInfo, TraderInfo memory traderInfo)
+    {
+        orderInfo = EXCHANGE.getOrderInfo(order);
+        traderInfo = getTraderInfo(order, takerAddress);
+        return (orderInfo, traderInfo);
+    }
+
+    /// @dev Fetches information for all passed in orders and the makers/takers of each order.
+    /// @param orders Array of order specifications.
+    /// @param takerAddresses Array of taker addresses corresponding to each order.
+    /// @return Arrays of OrderInfo and TraderInfo instances that correspond to each order.
+    function getOrdersAndTradersInfo(LibOrder.Order[] memory orders, address[] memory takerAddresses)
+        public
+        view
+        returns (LibOrder.OrderInfo[] memory ordersInfo, TraderInfo[] memory tradersInfo)
+    {
+        ordersInfo = EXCHANGE.getOrdersInfo(orders);
+        tradersInfo = getTradersInfo(orders, takerAddresses);
+        return (ordersInfo, tradersInfo);
+    }
+
+    /// @dev Fetches balance and allowances for maker and taker of order.
+    /// @param order The order structure.
+    /// @param takerAddress Address that will be filling the order.
+    /// @return Balances and allowances of maker and taker of order.
+    function getTraderInfo(LibOrder.Order memory order, address takerAddress)
+        public
+        view
+        returns (TraderInfo memory traderInfo)
+    {
+        (traderInfo.makerBalance, traderInfo.makerAllowance) = getBalanceAndAllowance(order.makerAddress, order.makerAssetData);
+        (traderInfo.takerBalance, traderInfo.takerAllowance) = getBalanceAndAllowance(takerAddress, order.takerAssetData);
+        bytes memory zrxAssetData = ZRX_ASSET_DATA;
+        (traderInfo.makerZrxBalance, traderInfo.makerZrxAllowance) = getBalanceAndAllowance(order.makerAddress, zrxAssetData);
+        (traderInfo.takerZrxBalance, traderInfo.takerZrxAllowance) = getBalanceAndAllowance(takerAddress, zrxAssetData);
+        return traderInfo;
+    }
+
+    /// @dev Fetches balances and allowances of maker and taker for each provided order.
+    /// @param orders Array of order specifications.
+    /// @param takerAddresses Array of taker addresses corresponding to each order.
+    /// @return Array of balances and allowances for maker and taker of each order.
+    function getTradersInfo(LibOrder.Order[] memory orders, address[] memory takerAddresses)
+        public
+        view
+        returns (TraderInfo[] memory)
+    {
+        uint256 ordersLength = orders.length;
+        TraderInfo[] memory tradersInfo = new TraderInfo[](ordersLength);
+        for (uint256 i = 0; i != ordersLength; i++) {
+            tradersInfo[i] = getTraderInfo(orders[i], takerAddresses[i]);
+        }
+        return tradersInfo;
+    }
+
+    /// @dev Fetches token balances and allowances of an address to given assetProxy. Supports ERC20 and ERC721.
+    /// @param target Address to fetch balances and allowances of.
+    /// @param assetData Encoded data that can be decoded by a specified proxy contract when transferring asset.
+    /// @return Balance of asset and allowance set to given proxy of asset.
+    ///         For ERC721 tokens, these values will always be 1 or 0.
+    function getBalanceAndAllowance(address target, bytes memory assetData)
+        public
+        view
+        returns (uint256 balance, uint256 allowance)
+    {
+        bytes4 assetProxyId = assetData.readBytes4(0);
+        address token = assetData.readAddress(16);
+        address assetProxy = EXCHANGE.getAssetProxy(assetProxyId);
+
+        if (assetProxyId == ERC20_DATA_ID) {
+            // Query balance
+            balance = IERC20Token(token).balanceOf(target);
+
+            // Query allowance
+            allowance = IERC20Token(token).allowance(target, assetProxy);
+        } else if (assetProxyId == ERC721_DATA_ID) {
+            uint256 tokenId = assetData.readUint256(36);
+
+            // Query owner of tokenId
+            address owner = getERC721TokenOwner(token, tokenId);
+
+            // Set balance to 1 if tokenId is owned by target
+            balance = target == owner ? 1 : 0;
+
+            // Check if ERC721Proxy is approved to spend tokenId
+            bool isApproved = IERC721Token(token).isApprovedForAll(target, assetProxy);
+            
+            // Set alowance to 1 if ERC721Proxy is approved to spend tokenId
+            allowance = isApproved ? 1 : 0;
+        } else {
+            revert("UNSUPPORTED_ASSET_PROXY");
+        }
+        return (balance, allowance);
+    }
+
+    /// @dev Fetches token balances and allowances of an address for each given assetProxy. Supports ERC20 and ERC721.
+    /// @param target Address to fetch balances and allowances of.
+    /// @param assetData Array of encoded byte arrays that can be decoded by a specified proxy contract when transferring asset.
+    /// @return Balances and allowances of assets.
+    ///         For ERC721 tokens, these values will always be 1 or 0.
+    function getBalancesAndAllowances(address target, bytes[] memory assetData)
+        public
+        view
+        returns (uint256[] memory, uint256[] memory)
+    {
+        uint256 length = assetData.length;
+        uint256[] memory balances = new uint256[](length);
+        uint256[] memory allowances = new uint256[](length);
+        for (uint256 i = 0; i != length; i++) {
+            (balances[i], allowances[i]) = getBalanceAndAllowance(target, assetData[i]);
+        }
+        return (balances, allowances);
+    }
+
+    /// @dev Calls `token.ownerOf(tokenId)`, but returns a null owner instead of reverting on an unowned token.
+    /// @param token Address of ERC721 token.
+    /// @param tokenId The identifier for the specific NFT.
+    /// @return Owner of tokenId or null address if unowned.
+    function getERC721TokenOwner(address token, uint256 tokenId)
+        public
+        view
+        returns (address owner)
+    {
+        assembly {
+            // load free memory pointer
+            let cdStart := mload(64)
+
+            // bytes4(keccak256(ownerOf(uint256))) = 0x6352211e
+            mstore(cdStart, 0x6352211e00000000000000000000000000000000000000000000000000000000)
+            mstore(add(cdStart, 4), tokenId)
+
+            // staticcall `ownerOf(tokenId)`
+            // `ownerOf` will revert if tokenId is not owned
+            let success := staticcall(
+                gas,      // forward all gas
+                token,    // call token contract
+                cdStart,  // start of calldata
+                36,       // length of input is 36 bytes
+                cdStart,  // write output over input
+                32        // size of output is 32 bytes
+            )
+
+            // Success implies that tokenId is owned
+            // Copy owner from return data if successful
+            if success {
+                owner := mload(cdStart)
+            }    
+        }
+
+        // Owner initialized to address(0), no need to modify if call is unsuccessful
+        return owner;
+    }
+}
diff --git a/contracts/extensions/package.json b/contracts/extensions/package.json
new file mode 100644
index 000000000..95db0c5ac
--- /dev/null
+++ b/contracts/extensions/package.json
@@ -0,0 +1,95 @@
+{
+    "private": true,
+    "name": "@0x/contracts-extensions",
+    "version": "1.0.0",
+    "engines": {
+        "node": ">=6.12"
+    },
+    "description": "Smart contract extensions of 0x protocol",
+    "main": "lib/src/index.js",
+    "directories": {
+        "test": "test"
+    },
+    "scripts": {
+        "build": "yarn pre_build && tsc -b",
+        "build:ci": "yarn build",
+        "pre_build": "run-s compile generate_contract_wrappers",
+        "test": "yarn run_mocha",
+        "rebuild_and_test": "run-s build test",
+        "test:coverage": "SOLIDITY_COVERAGE=true run-s build run_mocha coverage:report:text coverage:report:lcov",
+        "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",
+        "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",
+        "coverage:report:text": "istanbul report text",
+        "coverage:report:html": "istanbul report html && open coverage/index.html",
+        "profiler:report:html": "istanbul report html && open coverage/index.html",
+        "coverage:report:lcov": "istanbul report lcov",
+        "test:circleci": "yarn test",
+        "lint-contracts": "solhint contracts/**/**/**/**/*.sol"
+    },
+    "config": {
+        "abis": "generated-artifacts/@(DutchAuction|Forwarder|OrderValidator).json"
+    },
+    "repository": {
+        "type": "git",
+        "url": "https://github.com/0xProject/0x-monorepo.git"
+    },
+    "license": "Apache-2.0",
+    "bugs": {
+        "url": "https://github.com/0xProject/0x-monorepo/issues"
+    },
+    "homepage": "https://github.com/0xProject/0x-monorepo/contracts/core/README.md",
+    "devDependencies": {
+        "@0x/contracts-test-utils": "^1.0.0",
+        "@0x/abi-gen": "^1.0.17",
+        "@0x/dev-utils": "^1.0.19",
+        "@0x/sol-compiler": "^1.1.14",
+        "@0x/sol-cov": "^2.1.14",
+        "@0x/subproviders": "^2.1.6",
+        "@0x/tslint-config": "^1.0.10",
+        "@types/bn.js": "^4.11.0",
+        "@types/lodash": "4.14.104",
+        "@types/node": "*",
+        "@types/yargs": "^10.0.0",
+        "chai": "^4.0.1",
+        "chai-as-promised": "^7.1.0",
+        "chai-bignumber": "^2.0.1",
+        "dirty-chai": "^2.0.1",
+        "make-promises-safe": "^1.1.0",
+        "ethereumjs-abi": "0.6.5",
+        "mocha": "^4.1.0",
+        "npm-run-all": "^4.1.2",
+        "shx": "^0.2.2",
+        "solc": "^0.4.24",
+        "solhint": "^1.2.1",
+        "tslint": "5.11.0",
+        "typescript": "3.0.1",
+        "yargs": "^10.0.3"
+    },
+    "dependencies": {
+        "@0x/base-contract": "^3.0.8",
+        "@0x/order-utils": "^3.0.4",
+        "@0x/contracts-utils": "^1.0.0",
+        "@0x/contracts-core": "^2.1.56",
+        "@0x/contracts-tokens": "^1.0.0",
+        "@0x/contracts-libs": "^1.0.0",
+        "@0x/contracts-interfaces": "^1.0.0",
+        "@0x/types": "^1.3.0",
+        "@0x/typescript-typings": "^3.0.4",
+        "@0x/utils": "^2.0.6",
+        "@0x/web3-wrapper": "^3.1.6",
+        "@types/js-combinatorics": "^0.5.29",
+        "bn.js": "^4.11.8",
+        "ethereum-types": "^1.1.2",
+        "ethereumjs-util": "^5.1.1",
+        "lodash": "^4.17.5"
+    },
+    "publishConfig": {
+        "access": "public"
+    }
+}
diff --git a/contracts/extensions/src/artifacts/index.ts b/contracts/extensions/src/artifacts/index.ts
new file mode 100644
index 000000000..380bf0497
--- /dev/null
+++ b/contracts/extensions/src/artifacts/index.ts
@@ -0,0 +1,11 @@
+import { ContractArtifact } from 'ethereum-types';
+
+import * as DutchAuction from '../../generated-artifacts/DutchAuction.json';
+import * as Forwarder from '../../generated-artifacts/Forwarder.json';
+import * as OrderValidator from '../../generated-artifacts/OrderValidator.json';
+
+export const artifacts = {
+    DutchAuction: DutchAuction as ContractArtifact,
+    Forwarder: Forwarder as ContractArtifact,
+    OrderValidator: OrderValidator as ContractArtifact,
+};
diff --git a/contracts/extensions/src/index.ts b/contracts/extensions/src/index.ts
new file mode 100644
index 000000000..d55f08ea2
--- /dev/null
+++ b/contracts/extensions/src/index.ts
@@ -0,0 +1,2 @@
+export * from './artifacts';
+export * from './wrappers';
diff --git a/contracts/extensions/src/wrappers/index.ts b/contracts/extensions/src/wrappers/index.ts
new file mode 100644
index 000000000..30f74b56e
--- /dev/null
+++ b/contracts/extensions/src/wrappers/index.ts
@@ -0,0 +1,3 @@
+export * from '../../generated-wrappers/dutch_auction';
+export * from '../../generated-wrappers/forwarder';
+export * from '../../generated-wrappers/order_validator';
diff --git a/contracts/extensions/test/extensions/dutch_auction.ts b/contracts/extensions/test/extensions/dutch_auction.ts
new file mode 100644
index 000000000..2db3be752
--- /dev/null
+++ b/contracts/extensions/test/extensions/dutch_auction.ts
@@ -0,0 +1,458 @@
+import {
+    artifacts as coreArtifacts,
+    ERC20Wrapper,
+    ERC721Wrapper,
+    ExchangeContract,
+    ExchangeWrapper,
+} from '@0x/contracts-core';
+import {
+    chaiSetup,
+    constants,
+    ContractName,
+    ERC20BalancesByOwner,
+    expectTransactionFailedAsync,
+    getLatestBlockTimestampAsync,
+    OrderFactory,
+    provider,
+    txDefaults,
+    web3Wrapper,
+} from '@0x/contracts-test-utils';
+import {
+    artifacts as tokensArtifacts,
+    DummyERC20TokenContract,
+    DummyERC721TokenContract,
+    WETH9Contract,
+} from '@0x/contracts-tokens';
+import { BlockchainLifecycle } from '@0x/dev-utils';
+import { assetDataUtils, generatePseudoRandomSalt } from '@0x/order-utils';
+import { RevertReason, SignedOrder } from '@0x/types';
+import { BigNumber } from '@0x/utils';
+import { Web3Wrapper } from '@0x/web3-wrapper';
+import * as chai from 'chai';
+import ethAbi = require('ethereumjs-abi');
+import * as ethUtil from 'ethereumjs-util';
+import * as _ from 'lodash';
+
+import { DutchAuctionContract } from '../../generated-wrappers/dutch_auction';
+import { artifacts } from '../../src/artifacts';
+
+chaiSetup.configure();
+const expect = chai.expect;
+const blockchainLifecycle = new BlockchainLifecycle(web3Wrapper);
+const DECIMALS_DEFAULT = 18;
+
+describe(ContractName.DutchAuction, () => {
+    let makerAddress: string;
+    let owner: string;
+    let takerAddress: string;
+    let feeRecipientAddress: string;
+    let defaultMakerAssetAddress: string;
+
+    let zrxToken: DummyERC20TokenContract;
+    let erc20TokenA: DummyERC20TokenContract;
+    let erc721Token: DummyERC721TokenContract;
+    let dutchAuctionContract: DutchAuctionContract;
+    let wethContract: WETH9Contract;
+
+    let sellerOrderFactory: OrderFactory;
+    let buyerOrderFactory: OrderFactory;
+    let erc20Wrapper: ERC20Wrapper;
+    let erc20Balances: ERC20BalancesByOwner;
+    let currentBlockTimestamp: number;
+    let auctionBeginTimeSeconds: BigNumber;
+    let auctionEndTimeSeconds: BigNumber;
+    let auctionBeginAmount: BigNumber;
+    let auctionEndAmount: BigNumber;
+    let sellOrder: SignedOrder;
+    let buyOrder: SignedOrder;
+    let erc721MakerAssetIds: BigNumber[];
+    const tenMinutesInSeconds = 10 * 60;
+
+    function extendMakerAssetData(makerAssetData: string, beginTimeSeconds: BigNumber, beginAmount: BigNumber): string {
+        return ethUtil.bufferToHex(
+            Buffer.concat([
+                ethUtil.toBuffer(makerAssetData),
+                ethUtil.toBuffer(
+                    (ethAbi as any).rawEncode(
+                        ['uint256', 'uint256'],
+                        [beginTimeSeconds.toString(), beginAmount.toString()],
+                    ),
+                ),
+            ]),
+        );
+    }
+
+    before(async () => {
+        await blockchainLifecycle.startAsync();
+        const accounts = await web3Wrapper.getAvailableAddressesAsync();
+        const usedAddresses = ([owner, makerAddress, takerAddress, feeRecipientAddress] = accounts);
+
+        erc20Wrapper = new ERC20Wrapper(provider, usedAddresses, owner);
+
+        const numDummyErc20ToDeploy = 2;
+        [erc20TokenA, zrxToken] = await erc20Wrapper.deployDummyTokensAsync(
+            numDummyErc20ToDeploy,
+            constants.DUMMY_TOKEN_DECIMALS,
+        );
+        const erc20Proxy = await erc20Wrapper.deployProxyAsync();
+        await erc20Wrapper.setBalancesAndAllowancesAsync();
+
+        const erc721Wrapper = new ERC721Wrapper(provider, usedAddresses, owner);
+        [erc721Token] = await erc721Wrapper.deployDummyTokensAsync();
+        const erc721Proxy = await erc721Wrapper.deployProxyAsync();
+        await erc721Wrapper.setBalancesAndAllowancesAsync();
+        const erc721Balances = await erc721Wrapper.getBalancesAsync();
+        erc721MakerAssetIds = erc721Balances[makerAddress][erc721Token.address];
+
+        wethContract = await WETH9Contract.deployFrom0xArtifactAsync(tokensArtifacts.WETH9, provider, txDefaults);
+        erc20Wrapper.addDummyTokenContract(wethContract as any);
+
+        const zrxAssetData = assetDataUtils.encodeERC20AssetData(zrxToken.address);
+        const exchangeInstance = await ExchangeContract.deployFrom0xArtifactAsync(
+            coreArtifacts.Exchange,
+            provider,
+            txDefaults,
+            zrxAssetData,
+        );
+        const exchangeWrapper = new ExchangeWrapper(exchangeInstance, provider);
+        await exchangeWrapper.registerAssetProxyAsync(erc20Proxy.address, owner);
+        await exchangeWrapper.registerAssetProxyAsync(erc721Proxy.address, owner);
+
+        await erc20Proxy.addAuthorizedAddress.sendTransactionAsync(exchangeInstance.address, {
+            from: owner,
+        });
+        await erc721Proxy.addAuthorizedAddress.sendTransactionAsync(exchangeInstance.address, {
+            from: owner,
+        });
+
+        const dutchAuctionInstance = await DutchAuctionContract.deployFrom0xArtifactAsync(
+            artifacts.DutchAuction,
+            provider,
+            txDefaults,
+            exchangeInstance.address,
+        );
+        dutchAuctionContract = new DutchAuctionContract(
+            dutchAuctionInstance.abi,
+            dutchAuctionInstance.address,
+            provider,
+        );
+
+        defaultMakerAssetAddress = erc20TokenA.address;
+        const defaultTakerAssetAddress = wethContract.address;
+
+        // Set up taker WETH balance and allowance
+        await web3Wrapper.awaitTransactionSuccessAsync(
+            await wethContract.deposit.sendTransactionAsync({
+                from: takerAddress,
+                value: Web3Wrapper.toBaseUnitAmount(new BigNumber(50), DECIMALS_DEFAULT),
+            }),
+        );
+        await web3Wrapper.awaitTransactionSuccessAsync(
+            await wethContract.approve.sendTransactionAsync(
+                erc20Proxy.address,
+                constants.UNLIMITED_ALLOWANCE_IN_BASE_UNITS,
+                { from: takerAddress },
+            ),
+        );
+        web3Wrapper.abiDecoder.addABI(exchangeInstance.abi);
+        web3Wrapper.abiDecoder.addABI(zrxToken.abi);
+        erc20Wrapper.addTokenOwnerAddress(dutchAuctionContract.address);
+
+        currentBlockTimestamp = await getLatestBlockTimestampAsync();
+        // Default auction begins 10 minutes ago
+        auctionBeginTimeSeconds = new BigNumber(currentBlockTimestamp).minus(tenMinutesInSeconds);
+        // Default auction ends 10 from now
+        auctionEndTimeSeconds = new BigNumber(currentBlockTimestamp).plus(tenMinutesInSeconds);
+        auctionBeginAmount = Web3Wrapper.toBaseUnitAmount(new BigNumber(10), DECIMALS_DEFAULT);
+        auctionEndAmount = Web3Wrapper.toBaseUnitAmount(new BigNumber(1), DECIMALS_DEFAULT);
+
+        // Default sell order and buy order are exact mirrors
+        const sellerDefaultOrderParams = {
+            salt: generatePseudoRandomSalt(),
+            exchangeAddress: exchangeInstance.address,
+            makerAddress,
+            feeRecipientAddress,
+            // taker address or sender address should be set to the ducth auction contract
+            takerAddress: dutchAuctionContract.address,
+            makerAssetData: extendMakerAssetData(
+                assetDataUtils.encodeERC20AssetData(defaultMakerAssetAddress),
+                auctionBeginTimeSeconds,
+                auctionBeginAmount,
+            ),
+            takerAssetData: assetDataUtils.encodeERC20AssetData(defaultTakerAssetAddress),
+            makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(200), DECIMALS_DEFAULT),
+            takerAssetAmount: auctionEndAmount,
+            expirationTimeSeconds: auctionEndTimeSeconds,
+            makerFee: constants.ZERO_AMOUNT,
+            takerFee: constants.ZERO_AMOUNT,
+        };
+        // Default buy order is for the auction begin price
+        const buyerDefaultOrderParams = {
+            ...sellerDefaultOrderParams,
+            makerAddress: takerAddress,
+            makerAssetData: sellerDefaultOrderParams.takerAssetData,
+            takerAssetData: sellerDefaultOrderParams.makerAssetData,
+            makerAssetAmount: auctionBeginAmount,
+            takerAssetAmount: sellerDefaultOrderParams.makerAssetAmount,
+        };
+        const makerPrivateKey = constants.TESTRPC_PRIVATE_KEYS[accounts.indexOf(makerAddress)];
+        const takerPrivateKey = constants.TESTRPC_PRIVATE_KEYS[accounts.indexOf(takerAddress)];
+        sellerOrderFactory = new OrderFactory(makerPrivateKey, sellerDefaultOrderParams);
+        buyerOrderFactory = new OrderFactory(takerPrivateKey, buyerDefaultOrderParams);
+    });
+    after(async () => {
+        await blockchainLifecycle.revertAsync();
+    });
+    beforeEach(async () => {
+        await blockchainLifecycle.startAsync();
+        erc20Balances = await erc20Wrapper.getBalancesAsync();
+        sellOrder = await sellerOrderFactory.newSignedOrderAsync();
+        buyOrder = await buyerOrderFactory.newSignedOrderAsync();
+    });
+    afterEach(async () => {
+        await blockchainLifecycle.revertAsync();
+    });
+    describe('matchOrders', () => {
+        it('should be worth the begin price at the begining of the auction', async () => {
+            auctionBeginTimeSeconds = new BigNumber(currentBlockTimestamp + 2);
+            sellOrder = await sellerOrderFactory.newSignedOrderAsync({
+                makerAssetData: extendMakerAssetData(
+                    assetDataUtils.encodeERC20AssetData(defaultMakerAssetAddress),
+                    auctionBeginTimeSeconds,
+                    auctionBeginAmount,
+                ),
+            });
+            const auctionDetails = await dutchAuctionContract.getAuctionDetails.callAsync(sellOrder);
+            expect(auctionDetails.currentAmount).to.be.bignumber.equal(auctionBeginAmount);
+            expect(auctionDetails.beginAmount).to.be.bignumber.equal(auctionBeginAmount);
+        });
+        it('should be be worth the end price at the end of the auction', async () => {
+            auctionBeginTimeSeconds = new BigNumber(currentBlockTimestamp - tenMinutesInSeconds * 2);
+            auctionEndTimeSeconds = new BigNumber(currentBlockTimestamp - tenMinutesInSeconds);
+            sellOrder = await sellerOrderFactory.newSignedOrderAsync({
+                makerAssetData: extendMakerAssetData(
+                    assetDataUtils.encodeERC20AssetData(defaultMakerAssetAddress),
+                    auctionBeginTimeSeconds,
+                    auctionBeginAmount,
+                ),
+                expirationTimeSeconds: auctionEndTimeSeconds,
+            });
+            const auctionDetails = await dutchAuctionContract.getAuctionDetails.callAsync(sellOrder);
+            expect(auctionDetails.currentAmount).to.be.bignumber.equal(auctionEndAmount);
+            expect(auctionDetails.beginAmount).to.be.bignumber.equal(auctionBeginAmount);
+        });
+        it('should match orders at current amount and send excess to buyer', async () => {
+            const beforeAuctionDetails = await dutchAuctionContract.getAuctionDetails.callAsync(sellOrder);
+            buyOrder = await buyerOrderFactory.newSignedOrderAsync({
+                makerAssetAmount: beforeAuctionDetails.currentAmount.times(2),
+            });
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await dutchAuctionContract.matchOrders.sendTransactionAsync(
+                    buyOrder,
+                    sellOrder,
+                    buyOrder.signature,
+                    sellOrder.signature,
+                    {
+                        from: takerAddress,
+                    },
+                ),
+            );
+            const afterAuctionDetails = await dutchAuctionContract.getAuctionDetails.callAsync(sellOrder);
+            const newBalances = await erc20Wrapper.getBalancesAsync();
+            expect(newBalances[dutchAuctionContract.address][wethContract.address]).to.be.bignumber.equal(
+                constants.ZERO_AMOUNT,
+            );
+            // HACK gte used here due to a bug in ganache where the timestamp can change
+            // between multiple calls to the same block. Which can move the amount in our case
+            // ref: https://github.com/trufflesuite/ganache-core/issues/111
+            expect(newBalances[makerAddress][wethContract.address]).to.be.bignumber.gte(
+                erc20Balances[makerAddress][wethContract.address].plus(afterAuctionDetails.currentAmount),
+            );
+            expect(newBalances[takerAddress][wethContract.address]).to.be.bignumber.gte(
+                erc20Balances[takerAddress][wethContract.address].minus(beforeAuctionDetails.currentAmount),
+            );
+        });
+        it('maker fees on sellOrder are paid to the fee receipient', async () => {
+            sellOrder = await sellerOrderFactory.newSignedOrderAsync({
+                makerFee: new BigNumber(1),
+            });
+            const txHash = await dutchAuctionContract.matchOrders.sendTransactionAsync(
+                buyOrder,
+                sellOrder,
+                buyOrder.signature,
+                sellOrder.signature,
+                {
+                    from: takerAddress,
+                },
+            );
+            await web3Wrapper.awaitTransactionSuccessAsync(txHash);
+            const afterAuctionDetails = await dutchAuctionContract.getAuctionDetails.callAsync(sellOrder);
+            const newBalances = await erc20Wrapper.getBalancesAsync();
+            expect(newBalances[makerAddress][wethContract.address]).to.be.bignumber.gte(
+                erc20Balances[makerAddress][wethContract.address].plus(afterAuctionDetails.currentAmount),
+            );
+            expect(newBalances[feeRecipientAddress][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[feeRecipientAddress][zrxToken.address].plus(sellOrder.makerFee),
+            );
+        });
+        it('maker fees on buyOrder are paid to the fee receipient', async () => {
+            buyOrder = await buyerOrderFactory.newSignedOrderAsync({
+                makerFee: new BigNumber(1),
+            });
+            const txHash = await dutchAuctionContract.matchOrders.sendTransactionAsync(
+                buyOrder,
+                sellOrder,
+                buyOrder.signature,
+                sellOrder.signature,
+                {
+                    from: takerAddress,
+                },
+            );
+            await web3Wrapper.awaitTransactionSuccessAsync(txHash);
+            const newBalances = await erc20Wrapper.getBalancesAsync();
+            const afterAuctionDetails = await dutchAuctionContract.getAuctionDetails.callAsync(sellOrder);
+            expect(newBalances[makerAddress][wethContract.address]).to.be.bignumber.gte(
+                erc20Balances[makerAddress][wethContract.address].plus(afterAuctionDetails.currentAmount),
+            );
+            expect(newBalances[feeRecipientAddress][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[feeRecipientAddress][zrxToken.address].plus(buyOrder.makerFee),
+            );
+        });
+        it('should revert when auction expires', async () => {
+            auctionBeginTimeSeconds = new BigNumber(currentBlockTimestamp - tenMinutesInSeconds * 2);
+            auctionEndTimeSeconds = new BigNumber(currentBlockTimestamp - tenMinutesInSeconds);
+            sellOrder = await sellerOrderFactory.newSignedOrderAsync({
+                expirationTimeSeconds: auctionEndTimeSeconds,
+                makerAssetData: extendMakerAssetData(
+                    assetDataUtils.encodeERC20AssetData(defaultMakerAssetAddress),
+                    auctionBeginTimeSeconds,
+                    auctionBeginAmount,
+                ),
+            });
+            return expectTransactionFailedAsync(
+                dutchAuctionContract.matchOrders.sendTransactionAsync(
+                    buyOrder,
+                    sellOrder,
+                    buyOrder.signature,
+                    sellOrder.signature,
+                    {
+                        from: takerAddress,
+                    },
+                ),
+                RevertReason.AuctionExpired,
+            );
+        });
+        it('cannot be filled for less than the current price', async () => {
+            buyOrder = await buyerOrderFactory.newSignedOrderAsync({
+                makerAssetAmount: sellOrder.takerAssetAmount,
+            });
+            return expectTransactionFailedAsync(
+                dutchAuctionContract.matchOrders.sendTransactionAsync(
+                    buyOrder,
+                    sellOrder,
+                    buyOrder.signature,
+                    sellOrder.signature,
+                    {
+                        from: takerAddress,
+                    },
+                ),
+                RevertReason.AuctionInvalidAmount,
+            );
+        });
+        it('auction begin amount must be higher than final amount ', async () => {
+            sellOrder = await sellerOrderFactory.newSignedOrderAsync({
+                takerAssetAmount: auctionBeginAmount.plus(1),
+            });
+            return expectTransactionFailedAsync(
+                dutchAuctionContract.matchOrders.sendTransactionAsync(
+                    buyOrder,
+                    sellOrder,
+                    buyOrder.signature,
+                    sellOrder.signature,
+                    {
+                        from: takerAddress,
+                    },
+                ),
+                RevertReason.AuctionInvalidAmount,
+            );
+        });
+        it('begin time is less than end time', async () => {
+            auctionBeginTimeSeconds = new BigNumber(auctionEndTimeSeconds).plus(tenMinutesInSeconds);
+            sellOrder = await sellerOrderFactory.newSignedOrderAsync({
+                expirationTimeSeconds: auctionEndTimeSeconds,
+                makerAssetData: extendMakerAssetData(
+                    assetDataUtils.encodeERC20AssetData(defaultMakerAssetAddress),
+                    auctionBeginTimeSeconds,
+                    auctionBeginAmount,
+                ),
+            });
+            return expectTransactionFailedAsync(
+                dutchAuctionContract.matchOrders.sendTransactionAsync(
+                    buyOrder,
+                    sellOrder,
+                    buyOrder.signature,
+                    sellOrder.signature,
+                    {
+                        from: takerAddress,
+                    },
+                ),
+                RevertReason.AuctionInvalidBeginTime,
+            );
+        });
+        it('asset data contains auction parameters', async () => {
+            sellOrder = await sellerOrderFactory.newSignedOrderAsync({
+                makerAssetData: assetDataUtils.encodeERC20AssetData(defaultMakerAssetAddress),
+            });
+            return expectTransactionFailedAsync(
+                dutchAuctionContract.matchOrders.sendTransactionAsync(
+                    buyOrder,
+                    sellOrder,
+                    buyOrder.signature,
+                    sellOrder.signature,
+                    {
+                        from: takerAddress,
+                    },
+                ),
+                RevertReason.InvalidAssetData,
+            );
+        });
+        describe('ERC721', () => {
+            it('should match orders when ERC721', async () => {
+                const makerAssetId = erc721MakerAssetIds[0];
+                sellOrder = await sellerOrderFactory.newSignedOrderAsync({
+                    makerAssetAmount: new BigNumber(1),
+                    makerAssetData: extendMakerAssetData(
+                        assetDataUtils.encodeERC721AssetData(erc721Token.address, makerAssetId),
+                        auctionBeginTimeSeconds,
+                        auctionBeginAmount,
+                    ),
+                });
+                buyOrder = await buyerOrderFactory.newSignedOrderAsync({
+                    takerAssetAmount: new BigNumber(1),
+                    takerAssetData: sellOrder.makerAssetData,
+                });
+                await web3Wrapper.awaitTransactionSuccessAsync(
+                    await dutchAuctionContract.matchOrders.sendTransactionAsync(
+                        buyOrder,
+                        sellOrder,
+                        buyOrder.signature,
+                        sellOrder.signature,
+                        {
+                            from: takerAddress,
+                        },
+                    ),
+                );
+                const afterAuctionDetails = await dutchAuctionContract.getAuctionDetails.callAsync(sellOrder);
+                const newBalances = await erc20Wrapper.getBalancesAsync();
+                // HACK gte used here due to a bug in ganache where the timestamp can change
+                // between multiple calls to the same block. Which can move the amount in our case
+                // ref: https://github.com/trufflesuite/ganache-core/issues/111
+                expect(newBalances[makerAddress][wethContract.address]).to.be.bignumber.gte(
+                    erc20Balances[makerAddress][wethContract.address].plus(afterAuctionDetails.currentAmount),
+                );
+                const newOwner = await erc721Token.ownerOf.callAsync(makerAssetId);
+                expect(newOwner).to.be.bignumber.equal(takerAddress);
+            });
+        });
+    });
+});
diff --git a/contracts/extensions/test/extensions/forwarder.ts b/contracts/extensions/test/extensions/forwarder.ts
new file mode 100644
index 000000000..245d8eab9
--- /dev/null
+++ b/contracts/extensions/test/extensions/forwarder.ts
@@ -0,0 +1,1292 @@
+import {
+    artifacts as coreArtifacts,
+    ERC20Wrapper,
+    ERC721Wrapper,
+    ExchangeContract,
+    ExchangeWrapper,
+} from '@0x/contracts-core';
+import {
+    chaiSetup,
+    constants,
+    ContractName,
+    ERC20BalancesByOwner,
+    expectContractCreationFailedAsync,
+    expectTransactionFailedAsync,
+    OrderFactory,
+    provider,
+    sendTransactionResult,
+    txDefaults,
+    web3Wrapper,
+} from '@0x/contracts-test-utils';
+import {
+    artifacts as tokenArtifacts,
+    DummyERC20TokenContract,
+    DummyERC721TokenContract,
+    WETH9Contract,
+} from '@0x/contracts-tokens';
+import { BlockchainLifecycle } from '@0x/dev-utils';
+import { assetDataUtils } from '@0x/order-utils';
+import { 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 { ForwarderContract } from '../../generated-wrappers/forwarder';
+import { artifacts } from '../../src/artifacts';
+
+import { ForwarderWrapper } from '../utils/forwarder_wrapper';
+
+chaiSetup.configure();
+const expect = chai.expect;
+const blockchainLifecycle = new BlockchainLifecycle(web3Wrapper);
+const DECIMALS_DEFAULT = 18;
+const MAX_WETH_FILL_PERCENTAGE = 95;
+
+describe(ContractName.Forwarder, () => {
+    let makerAddress: string;
+    let owner: string;
+    let takerAddress: string;
+    let feeRecipientAddress: string;
+    let otherAddress: string;
+    let defaultMakerAssetAddress: string;
+    let zrxAssetData: string;
+    let wethAssetData: string;
+
+    let weth: DummyERC20TokenContract;
+    let zrxToken: DummyERC20TokenContract;
+    let erc20TokenA: DummyERC20TokenContract;
+    let erc721Token: DummyERC721TokenContract;
+    let forwarderContract: ForwarderContract;
+    let wethContract: WETH9Contract;
+    let forwarderWrapper: ForwarderWrapper;
+    let exchangeWrapper: ExchangeWrapper;
+
+    let orderWithoutFee: SignedOrder;
+    let orderWithFee: SignedOrder;
+    let feeOrder: SignedOrder;
+    let orderFactory: OrderFactory;
+    let erc20Wrapper: ERC20Wrapper;
+    let erc20Balances: ERC20BalancesByOwner;
+    let tx: TransactionReceiptWithDecodedLogs;
+
+    let erc721MakerAssetIds: BigNumber[];
+    let takerEthBalanceBefore: BigNumber;
+    let feePercentage: BigNumber;
+    let gasPrice: BigNumber;
+
+    before(async () => {
+        await blockchainLifecycle.startAsync();
+        const accounts = await web3Wrapper.getAvailableAddressesAsync();
+        const usedAddresses = ([owner, makerAddress, takerAddress, feeRecipientAddress, otherAddress] = accounts);
+
+        const txHash = await web3Wrapper.sendTransactionAsync({ from: accounts[0], to: accounts[0], value: 0 });
+        const transaction = await web3Wrapper.getTransactionByHashAsync(txHash);
+        gasPrice = new BigNumber(transaction.gasPrice);
+
+        const erc721Wrapper = new ERC721Wrapper(provider, usedAddresses, owner);
+        erc20Wrapper = new ERC20Wrapper(provider, usedAddresses, owner);
+
+        const numDummyErc20ToDeploy = 3;
+        [erc20TokenA, zrxToken] = await erc20Wrapper.deployDummyTokensAsync(
+            numDummyErc20ToDeploy,
+            constants.DUMMY_TOKEN_DECIMALS,
+        );
+        const erc20Proxy = await erc20Wrapper.deployProxyAsync();
+        await erc20Wrapper.setBalancesAndAllowancesAsync();
+
+        [erc721Token] = await erc721Wrapper.deployDummyTokensAsync();
+        const erc721Proxy = await erc721Wrapper.deployProxyAsync();
+        await erc721Wrapper.setBalancesAndAllowancesAsync();
+        const erc721Balances = await erc721Wrapper.getBalancesAsync();
+        erc721MakerAssetIds = erc721Balances[makerAddress][erc721Token.address];
+
+        wethContract = await WETH9Contract.deployFrom0xArtifactAsync(tokenArtifacts.WETH9, provider, txDefaults);
+        weth = new DummyERC20TokenContract(wethContract.abi, wethContract.address, provider);
+        erc20Wrapper.addDummyTokenContract(weth);
+
+        wethAssetData = assetDataUtils.encodeERC20AssetData(wethContract.address);
+        zrxAssetData = assetDataUtils.encodeERC20AssetData(zrxToken.address);
+        const exchangeInstance = await ExchangeContract.deployFrom0xArtifactAsync(
+            coreArtifacts.Exchange,
+            provider,
+            txDefaults,
+            zrxAssetData,
+        );
+        exchangeWrapper = new ExchangeWrapper(exchangeInstance, provider);
+        await exchangeWrapper.registerAssetProxyAsync(erc20Proxy.address, owner);
+        await exchangeWrapper.registerAssetProxyAsync(erc721Proxy.address, owner);
+
+        await erc20Proxy.addAuthorizedAddress.sendTransactionAsync(exchangeInstance.address, {
+            from: owner,
+        });
+        await erc721Proxy.addAuthorizedAddress.sendTransactionAsync(exchangeInstance.address, {
+            from: owner,
+        });
+
+        defaultMakerAssetAddress = erc20TokenA.address;
+        const defaultTakerAssetAddress = wethContract.address;
+        const defaultOrderParams = {
+            exchangeAddress: exchangeInstance.address,
+            makerAddress,
+            feeRecipientAddress,
+            makerAssetData: assetDataUtils.encodeERC20AssetData(defaultMakerAssetAddress),
+            takerAssetData: assetDataUtils.encodeERC20AssetData(defaultTakerAssetAddress),
+            makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(200), DECIMALS_DEFAULT),
+            takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), DECIMALS_DEFAULT),
+            makerFee: Web3Wrapper.toBaseUnitAmount(new BigNumber(1), DECIMALS_DEFAULT),
+            takerFee: Web3Wrapper.toBaseUnitAmount(new BigNumber(0), DECIMALS_DEFAULT),
+        };
+        const privateKey = constants.TESTRPC_PRIVATE_KEYS[accounts.indexOf(makerAddress)];
+        orderFactory = new OrderFactory(privateKey, defaultOrderParams);
+
+        const forwarderInstance = await ForwarderContract.deployFrom0xArtifactAsync(
+            artifacts.Forwarder,
+            provider,
+            txDefaults,
+            exchangeInstance.address,
+            zrxAssetData,
+            wethAssetData,
+        );
+        forwarderContract = new ForwarderContract(forwarderInstance.abi, forwarderInstance.address, provider);
+        forwarderWrapper = new ForwarderWrapper(forwarderContract, provider);
+        const zrxDepositAmount = Web3Wrapper.toBaseUnitAmount(new BigNumber(10000), 18);
+        await web3Wrapper.awaitTransactionSuccessAsync(
+            await zrxToken.transfer.sendTransactionAsync(forwarderContract.address, zrxDepositAmount),
+        );
+        erc20Wrapper.addTokenOwnerAddress(forwarderInstance.address);
+    });
+    after(async () => {
+        await blockchainLifecycle.revertAsync();
+    });
+    beforeEach(async () => {
+        await blockchainLifecycle.startAsync();
+        erc20Balances = await erc20Wrapper.getBalancesAsync();
+        takerEthBalanceBefore = await web3Wrapper.getBalanceInWeiAsync(takerAddress);
+        orderWithoutFee = await orderFactory.newSignedOrderAsync();
+        feeOrder = await orderFactory.newSignedOrderAsync({
+            makerAssetData: assetDataUtils.encodeERC20AssetData(zrxToken.address),
+            takerFee: Web3Wrapper.toBaseUnitAmount(new BigNumber(1), DECIMALS_DEFAULT),
+        });
+        orderWithFee = await orderFactory.newSignedOrderAsync({
+            takerFee: Web3Wrapper.toBaseUnitAmount(new BigNumber(1), DECIMALS_DEFAULT),
+        });
+    });
+    afterEach(async () => {
+        await blockchainLifecycle.revertAsync();
+    });
+
+    describe('constructor', () => {
+        it('should revert if assetProxy is unregistered', async () => {
+            const exchangeInstance = await ExchangeContract.deployFrom0xArtifactAsync(
+                coreArtifacts.Exchange,
+                provider,
+                txDefaults,
+                zrxAssetData,
+            );
+            return expectContractCreationFailedAsync(
+                (ForwarderContract.deployFrom0xArtifactAsync(
+                    artifacts.Forwarder,
+                    provider,
+                    txDefaults,
+                    exchangeInstance.address,
+                    zrxAssetData,
+                    wethAssetData,
+                ) as any) as sendTransactionResult,
+                RevertReason.UnregisteredAssetProxy,
+            );
+        });
+    });
+    describe('marketSellOrdersWithEth without extra fees', () => {
+        it('should fill a single order', async () => {
+            const ordersWithoutFee = [orderWithoutFee];
+            const feeOrders: SignedOrder[] = [];
+            const ethValue = orderWithoutFee.takerAssetAmount.dividedToIntegerBy(2);
+
+            tx = await forwarderWrapper.marketSellOrdersWithEthAsync(ordersWithoutFee, feeOrders, {
+                value: ethValue,
+                from: takerAddress,
+            });
+            const takerEthBalanceAfter = await web3Wrapper.getBalanceInWeiAsync(takerAddress);
+            const forwarderEthBalance = await web3Wrapper.getBalanceInWeiAsync(forwarderContract.address);
+            const newBalances = await erc20Wrapper.getBalancesAsync();
+
+            const primaryTakerAssetFillAmount = ForwarderWrapper.getPercentageOfValue(
+                ethValue,
+                MAX_WETH_FILL_PERCENTAGE,
+            );
+            const makerAssetFillAmount = primaryTakerAssetFillAmount
+                .times(orderWithoutFee.makerAssetAmount)
+                .dividedToIntegerBy(orderWithoutFee.takerAssetAmount);
+            const totalEthSpent = primaryTakerAssetFillAmount.plus(gasPrice.times(tx.gasUsed));
+
+            expect(takerEthBalanceAfter).to.be.bignumber.equal(takerEthBalanceBefore.minus(totalEthSpent));
+            expect(newBalances[makerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][defaultMakerAssetAddress].minus(makerAssetFillAmount),
+            );
+            expect(newBalances[takerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[takerAddress][defaultMakerAssetAddress].plus(makerAssetFillAmount),
+            );
+            expect(newBalances[makerAddress][weth.address]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][weth.address].plus(primaryTakerAssetFillAmount),
+            );
+            expect(newBalances[forwarderContract.address][weth.address]).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(newBalances[forwarderContract.address][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                constants.ZERO_AMOUNT,
+            );
+            expect(forwarderEthBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+        });
+        it('should fill multiple orders', async () => {
+            const secondOrderWithoutFee = await orderFactory.newSignedOrderAsync();
+            const ordersWithoutFee = [orderWithoutFee, secondOrderWithoutFee];
+            const feeOrders: SignedOrder[] = [];
+            const ethValue = ordersWithoutFee[0].takerAssetAmount.plus(
+                ordersWithoutFee[1].takerAssetAmount.dividedToIntegerBy(2),
+            );
+
+            tx = await forwarderWrapper.marketSellOrdersWithEthAsync(ordersWithoutFee, feeOrders, {
+                value: ethValue,
+                from: takerAddress,
+            });
+            const takerEthBalanceAfter = await web3Wrapper.getBalanceInWeiAsync(takerAddress);
+            const forwarderEthBalance = await web3Wrapper.getBalanceInWeiAsync(forwarderContract.address);
+            const newBalances = await erc20Wrapper.getBalancesAsync();
+
+            const primaryTakerAssetFillAmount = ForwarderWrapper.getPercentageOfValue(
+                ethValue,
+                MAX_WETH_FILL_PERCENTAGE,
+            );
+            const firstTakerAssetFillAmount = ordersWithoutFee[0].takerAssetAmount;
+            const secondTakerAssetFillAmount = primaryTakerAssetFillAmount.minus(firstTakerAssetFillAmount);
+
+            const makerAssetFillAmount = ordersWithoutFee[0].makerAssetAmount.plus(
+                ordersWithoutFee[1].makerAssetAmount
+                    .times(secondTakerAssetFillAmount)
+                    .dividedToIntegerBy(ordersWithoutFee[1].takerAssetAmount),
+            );
+            const totalEthSpent = primaryTakerAssetFillAmount.plus(gasPrice.times(tx.gasUsed));
+            expect(takerEthBalanceAfter).to.be.bignumber.equal(takerEthBalanceBefore.minus(totalEthSpent));
+            expect(newBalances[makerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][defaultMakerAssetAddress].minus(makerAssetFillAmount),
+            );
+            expect(newBalances[takerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[takerAddress][defaultMakerAssetAddress].plus(makerAssetFillAmount),
+            );
+            expect(newBalances[makerAddress][weth.address]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][weth.address].plus(primaryTakerAssetFillAmount),
+            );
+            expect(newBalances[forwarderContract.address][weth.address]).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(newBalances[forwarderContract.address][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                constants.ZERO_AMOUNT,
+            );
+            expect(forwarderEthBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+        });
+        it('should fill the order and pay ZRX fees from a single feeOrder', async () => {
+            const ordersWithFee = [orderWithFee];
+            const feeOrders = [feeOrder];
+            const ethValue = orderWithFee.takerAssetAmount.dividedToIntegerBy(2);
+
+            tx = await forwarderWrapper.marketSellOrdersWithEthAsync(ordersWithFee, feeOrders, {
+                value: ethValue,
+                from: takerAddress,
+            });
+            const takerEthBalanceAfter = await web3Wrapper.getBalanceInWeiAsync(takerAddress);
+            const forwarderEthBalance = await web3Wrapper.getBalanceInWeiAsync(forwarderContract.address);
+            const newBalances = await erc20Wrapper.getBalancesAsync();
+
+            const primaryTakerAssetFillAmount = ForwarderWrapper.getPercentageOfValue(
+                ethValue,
+                MAX_WETH_FILL_PERCENTAGE,
+            );
+            const makerAssetFillAmount = primaryTakerAssetFillAmount
+                .times(orderWithoutFee.makerAssetAmount)
+                .dividedToIntegerBy(orderWithoutFee.takerAssetAmount);
+            const feeAmount = ForwarderWrapper.getPercentageOfValue(
+                orderWithFee.takerFee.dividedToIntegerBy(2),
+                MAX_WETH_FILL_PERCENTAGE,
+            );
+            const wethSpentOnFeeOrders = ForwarderWrapper.getWethForFeeOrders(feeAmount, feeOrders);
+            const totalEthSpent = primaryTakerAssetFillAmount
+                .plus(wethSpentOnFeeOrders)
+                .plus(gasPrice.times(tx.gasUsed));
+
+            expect(takerEthBalanceAfter).to.be.bignumber.equal(takerEthBalanceBefore.minus(totalEthSpent));
+            expect(newBalances[makerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][defaultMakerAssetAddress].minus(makerAssetFillAmount),
+            );
+            expect(newBalances[takerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[takerAddress][defaultMakerAssetAddress].plus(makerAssetFillAmount),
+            );
+            expect(newBalances[makerAddress][weth.address]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][weth.address].plus(primaryTakerAssetFillAmount).plus(wethSpentOnFeeOrders),
+            );
+            expect(newBalances[forwarderContract.address][weth.address]).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(newBalances[forwarderContract.address][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                constants.ZERO_AMOUNT,
+            );
+            expect(forwarderEthBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+        });
+        it('should fill the orders and pay ZRX from multiple feeOrders', async () => {
+            const ordersWithFee = [orderWithFee];
+            const ethValue = orderWithFee.takerAssetAmount;
+            const makerAssetData = assetDataUtils.encodeERC20AssetData(zrxToken.address);
+            const makerAssetAmount = orderWithFee.takerFee.dividedToIntegerBy(2);
+            const takerAssetAmount = feeOrder.takerAssetAmount
+                .times(makerAssetAmount)
+                .dividedToIntegerBy(feeOrder.makerAssetAmount);
+
+            const firstFeeOrder = await orderFactory.newSignedOrderAsync({
+                makerAssetData,
+                makerAssetAmount,
+                takerAssetAmount,
+            });
+            const secondFeeOrder = await orderFactory.newSignedOrderAsync({
+                makerAssetData,
+                makerAssetAmount,
+                takerAssetAmount,
+            });
+            const feeOrders = [firstFeeOrder, secondFeeOrder];
+
+            tx = await forwarderWrapper.marketSellOrdersWithEthAsync(ordersWithFee, feeOrders, {
+                value: ethValue,
+                from: takerAddress,
+            });
+            const takerEthBalanceAfter = await web3Wrapper.getBalanceInWeiAsync(takerAddress);
+            const forwarderEthBalance = await web3Wrapper.getBalanceInWeiAsync(forwarderContract.address);
+            const newBalances = await erc20Wrapper.getBalancesAsync();
+
+            const primaryTakerAssetFillAmount = ForwarderWrapper.getPercentageOfValue(
+                ethValue,
+                MAX_WETH_FILL_PERCENTAGE,
+            );
+            const makerAssetFillAmount = primaryTakerAssetFillAmount
+                .times(orderWithoutFee.makerAssetAmount)
+                .dividedToIntegerBy(orderWithoutFee.takerAssetAmount);
+            const feeAmount = ForwarderWrapper.getPercentageOfValue(orderWithFee.takerFee, MAX_WETH_FILL_PERCENTAGE);
+            const wethSpentOnFeeOrders = ForwarderWrapper.getWethForFeeOrders(feeAmount, feeOrders);
+            const totalEthSpent = primaryTakerAssetFillAmount
+                .plus(wethSpentOnFeeOrders)
+                .plus(gasPrice.times(tx.gasUsed));
+
+            expect(takerEthBalanceAfter).to.be.bignumber.equal(takerEthBalanceBefore.minus(totalEthSpent));
+            expect(newBalances[makerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][defaultMakerAssetAddress].minus(makerAssetFillAmount),
+            );
+            expect(newBalances[takerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[takerAddress][defaultMakerAssetAddress].plus(makerAssetFillAmount),
+            );
+            expect(newBalances[makerAddress][weth.address]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][weth.address].plus(primaryTakerAssetFillAmount).plus(wethSpentOnFeeOrders),
+            );
+            expect(newBalances[forwarderContract.address][weth.address]).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(newBalances[forwarderContract.address][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                constants.ZERO_AMOUNT,
+            );
+            expect(forwarderEthBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+        });
+        it('should fill the order when token is ZRX with fees', async () => {
+            orderWithFee = await orderFactory.newSignedOrderAsync({
+                makerAssetData: assetDataUtils.encodeERC20AssetData(zrxToken.address),
+                takerFee: Web3Wrapper.toBaseUnitAmount(new BigNumber(1), DECIMALS_DEFAULT),
+            });
+            const ordersWithFee = [orderWithFee];
+            const feeOrders: SignedOrder[] = [];
+            const ethValue = orderWithFee.takerAssetAmount.dividedToIntegerBy(2);
+
+            tx = await forwarderWrapper.marketSellOrdersWithEthAsync(ordersWithFee, feeOrders, {
+                value: ethValue,
+                from: takerAddress,
+            });
+            const takerEthBalanceAfter = await web3Wrapper.getBalanceInWeiAsync(takerAddress);
+            const forwarderEthBalance = await web3Wrapper.getBalanceInWeiAsync(forwarderContract.address);
+            const newBalances = await erc20Wrapper.getBalancesAsync();
+
+            const makerAssetFillAmount = orderWithFee.makerAssetAmount.dividedToIntegerBy(2);
+            const totalEthSpent = ethValue.plus(gasPrice.times(tx.gasUsed));
+            const takerFeePaid = orderWithFee.takerFee.dividedToIntegerBy(2);
+            const makerFeePaid = orderWithFee.makerFee.dividedToIntegerBy(2);
+
+            expect(takerEthBalanceAfter).to.be.bignumber.equal(takerEthBalanceBefore.minus(totalEthSpent));
+            expect(newBalances[makerAddress][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][zrxToken.address].minus(makerAssetFillAmount).minus(makerFeePaid),
+            );
+            expect(newBalances[takerAddress][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[takerAddress][zrxToken.address].plus(makerAssetFillAmount).minus(takerFeePaid),
+            );
+            expect(newBalances[makerAddress][weth.address]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][weth.address].plus(ethValue),
+            );
+            expect(newBalances[forwarderContract.address][weth.address]).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(newBalances[forwarderContract.address][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[forwarderContract.address][zrxToken.address],
+            );
+            expect(forwarderEthBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+        });
+        it('should refund remaining ETH if amount is greater than takerAssetAmount', async () => {
+            const ordersWithoutFee = [orderWithoutFee];
+            const feeOrders: SignedOrder[] = [];
+            const ethValue = orderWithoutFee.takerAssetAmount.times(2);
+
+            tx = await forwarderWrapper.marketSellOrdersWithEthAsync(ordersWithoutFee, feeOrders, {
+                value: ethValue,
+                from: takerAddress,
+            });
+            const takerEthBalanceAfter = await web3Wrapper.getBalanceInWeiAsync(takerAddress);
+            const totalEthSpent = orderWithoutFee.takerAssetAmount.plus(gasPrice.times(tx.gasUsed));
+
+            expect(takerEthBalanceAfter).to.be.bignumber.equal(takerEthBalanceBefore.minus(totalEthSpent));
+        });
+        it('should revert if ZRX cannot be fully repurchased', async () => {
+            orderWithFee = await orderFactory.newSignedOrderAsync({
+                takerFee: Web3Wrapper.toBaseUnitAmount(new BigNumber(50), DECIMALS_DEFAULT),
+            });
+            const ordersWithFee = [orderWithFee];
+            feeOrder = await orderFactory.newSignedOrderAsync({
+                makerAssetData: assetDataUtils.encodeERC20AssetData(zrxToken.address),
+                makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(1), DECIMALS_DEFAULT),
+            });
+            const feeOrders = [feeOrder];
+            const ethValue = orderWithFee.takerAssetAmount;
+            return expectTransactionFailedAsync(
+                forwarderWrapper.marketSellOrdersWithEthAsync(ordersWithFee, feeOrders, {
+                    value: ethValue,
+                    from: takerAddress,
+                }),
+                RevertReason.CompleteFillFailed,
+            );
+        });
+        it('should not fill orders with different makerAssetData than the first order', async () => {
+            const makerAssetId = erc721MakerAssetIds[0];
+            const erc721SignedOrder = await orderFactory.newSignedOrderAsync({
+                makerAssetAmount: new BigNumber(1),
+                makerAssetData: assetDataUtils.encodeERC721AssetData(erc721Token.address, makerAssetId),
+            });
+            const erc20SignedOrder = await orderFactory.newSignedOrderAsync();
+            const ordersWithoutFee = [erc20SignedOrder, erc721SignedOrder];
+            const feeOrders: SignedOrder[] = [];
+            const ethValue = erc20SignedOrder.takerAssetAmount.plus(erc721SignedOrder.takerAssetAmount);
+
+            tx = await forwarderWrapper.marketSellOrdersWithEthAsync(ordersWithoutFee, feeOrders, {
+                value: ethValue,
+                from: takerAddress,
+            });
+            const takerEthBalanceAfter = await web3Wrapper.getBalanceInWeiAsync(takerAddress);
+            const totalEthSpent = erc20SignedOrder.takerAssetAmount.plus(gasPrice.times(tx.gasUsed));
+
+            expect(takerEthBalanceAfter).to.be.bignumber.equal(takerEthBalanceBefore.minus(totalEthSpent));
+        });
+    });
+    describe('marketSellOrdersWithEth with extra fees', () => {
+        it('should fill the order and send fee to feeRecipient', async () => {
+            const ordersWithoutFee = [orderWithoutFee];
+            const feeOrders: SignedOrder[] = [];
+            const ethValue = orderWithoutFee.takerAssetAmount.div(2);
+
+            const baseFeePercentage = 2;
+            feePercentage = ForwarderWrapper.getPercentageOfValue(constants.PERCENTAGE_DENOMINATOR, baseFeePercentage);
+            const feeRecipientEthBalanceBefore = await web3Wrapper.getBalanceInWeiAsync(feeRecipientAddress);
+            tx = await forwarderWrapper.marketSellOrdersWithEthAsync(
+                ordersWithoutFee,
+                feeOrders,
+                {
+                    value: ethValue,
+                    from: takerAddress,
+                },
+                { feePercentage, feeRecipient: feeRecipientAddress },
+            );
+            const takerEthBalanceAfter = await web3Wrapper.getBalanceInWeiAsync(takerAddress);
+            const feeRecipientEthBalanceAfter = await web3Wrapper.getBalanceInWeiAsync(feeRecipientAddress);
+            const forwarderEthBalance = await web3Wrapper.getBalanceInWeiAsync(forwarderContract.address);
+            const newBalances = await erc20Wrapper.getBalancesAsync();
+
+            const primaryTakerAssetFillAmount = ForwarderWrapper.getPercentageOfValue(
+                ethValue,
+                MAX_WETH_FILL_PERCENTAGE,
+            );
+            const makerAssetFillAmount = primaryTakerAssetFillAmount
+                .times(orderWithoutFee.makerAssetAmount)
+                .dividedToIntegerBy(orderWithoutFee.takerAssetAmount);
+            const ethSpentOnFee = ForwarderWrapper.getPercentageOfValue(primaryTakerAssetFillAmount, baseFeePercentage);
+            const totalEthSpent = primaryTakerAssetFillAmount.plus(ethSpentOnFee).plus(gasPrice.times(tx.gasUsed));
+
+            expect(takerEthBalanceAfter).to.be.bignumber.equal(takerEthBalanceBefore.minus(totalEthSpent));
+            expect(newBalances[makerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][defaultMakerAssetAddress].minus(makerAssetFillAmount),
+            );
+            expect(newBalances[takerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[takerAddress][defaultMakerAssetAddress].plus(makerAssetFillAmount),
+            );
+            expect(newBalances[makerAddress][weth.address]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][weth.address].plus(primaryTakerAssetFillAmount),
+            );
+            expect(newBalances[forwarderContract.address][weth.address]).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(newBalances[forwarderContract.address][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                constants.ZERO_AMOUNT,
+            );
+            expect(feeRecipientEthBalanceAfter).to.be.bignumber.equal(feeRecipientEthBalanceBefore.plus(ethSpentOnFee));
+            expect(forwarderEthBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+        });
+        it('should fail if the fee is set too high', async () => {
+            const ethValue = orderWithoutFee.takerAssetAmount.div(2);
+            const baseFeePercentage = 6;
+            feePercentage = ForwarderWrapper.getPercentageOfValue(ethValue, baseFeePercentage);
+            const ordersWithoutFee = [orderWithoutFee];
+            const feeOrders: SignedOrder[] = [];
+            await expectTransactionFailedAsync(
+                forwarderWrapper.marketSellOrdersWithEthAsync(
+                    ordersWithoutFee,
+                    feeOrders,
+                    { from: takerAddress, value: ethValue, gasPrice },
+                    { feePercentage, feeRecipient: feeRecipientAddress },
+                ),
+                RevertReason.FeePercentageTooLarge,
+            );
+        });
+        it('should fail if there is not enough ETH remaining to pay the fee', async () => {
+            const ethValue = orderWithoutFee.takerAssetAmount.div(2);
+            const baseFeePercentage = 5;
+            feePercentage = ForwarderWrapper.getPercentageOfValue(constants.PERCENTAGE_DENOMINATOR, baseFeePercentage);
+            const ordersWithFee = [orderWithFee];
+            const feeOrders = [feeOrder];
+            await expectTransactionFailedAsync(
+                forwarderWrapper.marketSellOrdersWithEthAsync(
+                    ordersWithFee,
+                    feeOrders,
+                    { from: takerAddress, value: ethValue, gasPrice },
+                    { feePercentage, feeRecipient: feeRecipientAddress },
+                ),
+                RevertReason.InsufficientEthRemaining,
+            );
+        });
+    });
+    describe('marketBuyOrdersWithEth without extra fees', () => {
+        it('should buy the exact amount of makerAsset in a single order', async () => {
+            const ordersWithoutFee = [orderWithoutFee];
+            const feeOrders: SignedOrder[] = [];
+            const makerAssetFillAmount = orderWithoutFee.makerAssetAmount.dividedToIntegerBy(2);
+            const ethValue = orderWithoutFee.takerAssetAmount.dividedToIntegerBy(2);
+
+            tx = await forwarderWrapper.marketBuyOrdersWithEthAsync(ordersWithoutFee, feeOrders, makerAssetFillAmount, {
+                value: ethValue,
+                from: takerAddress,
+            });
+            const takerEthBalanceAfter = await web3Wrapper.getBalanceInWeiAsync(takerAddress);
+            const forwarderEthBalance = await web3Wrapper.getBalanceInWeiAsync(forwarderContract.address);
+            const newBalances = await erc20Wrapper.getBalancesAsync();
+
+            const primaryTakerAssetFillAmount = ethValue;
+            const totalEthSpent = primaryTakerAssetFillAmount.plus(gasPrice.times(tx.gasUsed));
+
+            expect(takerEthBalanceAfter).to.be.bignumber.equal(takerEthBalanceBefore.minus(totalEthSpent));
+            expect(newBalances[makerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][defaultMakerAssetAddress].minus(makerAssetFillAmount),
+            );
+            expect(newBalances[takerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[takerAddress][defaultMakerAssetAddress].plus(makerAssetFillAmount),
+            );
+            expect(newBalances[makerAddress][weth.address]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][weth.address].plus(primaryTakerAssetFillAmount),
+            );
+            expect(newBalances[forwarderContract.address][weth.address]).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(newBalances[forwarderContract.address][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                constants.ZERO_AMOUNT,
+            );
+            expect(forwarderEthBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+        });
+        it('should buy the exact amount of makerAsset in multiple orders', async () => {
+            const secondOrderWithoutFee = await orderFactory.newSignedOrderAsync();
+            const ordersWithoutFee = [orderWithoutFee, secondOrderWithoutFee];
+            const feeOrders: SignedOrder[] = [];
+            const makerAssetFillAmount = ordersWithoutFee[0].makerAssetAmount.plus(
+                ordersWithoutFee[1].makerAssetAmount.dividedToIntegerBy(2),
+            );
+            const ethValue = ordersWithoutFee[0].takerAssetAmount.plus(
+                ordersWithoutFee[1].takerAssetAmount.dividedToIntegerBy(2),
+            );
+
+            tx = await forwarderWrapper.marketBuyOrdersWithEthAsync(ordersWithoutFee, feeOrders, makerAssetFillAmount, {
+                value: ethValue,
+                from: takerAddress,
+            });
+            const takerEthBalanceAfter = await web3Wrapper.getBalanceInWeiAsync(takerAddress);
+            const forwarderEthBalance = await web3Wrapper.getBalanceInWeiAsync(forwarderContract.address);
+            const newBalances = await erc20Wrapper.getBalancesAsync();
+
+            const primaryTakerAssetFillAmount = ethValue;
+            const totalEthSpent = primaryTakerAssetFillAmount.plus(gasPrice.times(tx.gasUsed));
+
+            expect(takerEthBalanceAfter).to.be.bignumber.equal(takerEthBalanceBefore.minus(totalEthSpent));
+            expect(newBalances[makerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][defaultMakerAssetAddress].minus(makerAssetFillAmount),
+            );
+            expect(newBalances[takerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[takerAddress][defaultMakerAssetAddress].plus(makerAssetFillAmount),
+            );
+            expect(newBalances[makerAddress][weth.address]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][weth.address].plus(primaryTakerAssetFillAmount),
+            );
+            expect(newBalances[forwarderContract.address][weth.address]).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(newBalances[forwarderContract.address][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                constants.ZERO_AMOUNT,
+            );
+            expect(forwarderEthBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+        });
+        it('should buy the exact amount of makerAsset and return excess ETH', async () => {
+            const ordersWithoutFee = [orderWithoutFee];
+            const feeOrders: SignedOrder[] = [];
+            const makerAssetFillAmount = orderWithoutFee.makerAssetAmount.dividedToIntegerBy(2);
+            const ethValue = orderWithoutFee.takerAssetAmount;
+
+            tx = await forwarderWrapper.marketBuyOrdersWithEthAsync(ordersWithoutFee, feeOrders, makerAssetFillAmount, {
+                value: ethValue,
+                from: takerAddress,
+            });
+            const takerEthBalanceAfter = await web3Wrapper.getBalanceInWeiAsync(takerAddress);
+            const forwarderEthBalance = await web3Wrapper.getBalanceInWeiAsync(forwarderContract.address);
+            const newBalances = await erc20Wrapper.getBalancesAsync();
+
+            const primaryTakerAssetFillAmount = ethValue.dividedToIntegerBy(2);
+            const totalEthSpent = primaryTakerAssetFillAmount.plus(gasPrice.times(tx.gasUsed));
+
+            expect(takerEthBalanceAfter).to.be.bignumber.equal(takerEthBalanceBefore.minus(totalEthSpent));
+            expect(newBalances[makerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][defaultMakerAssetAddress].minus(makerAssetFillAmount),
+            );
+            expect(newBalances[takerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[takerAddress][defaultMakerAssetAddress].plus(makerAssetFillAmount),
+            );
+            expect(newBalances[makerAddress][weth.address]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][weth.address].plus(primaryTakerAssetFillAmount),
+            );
+            expect(newBalances[forwarderContract.address][weth.address]).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(newBalances[forwarderContract.address][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                constants.ZERO_AMOUNT,
+            );
+            expect(forwarderEthBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+        });
+        it('should buy the exact amount of makerAsset and pay ZRX from feeOrders', async () => {
+            const ordersWithFee = [orderWithFee];
+            const feeOrders = [feeOrder];
+            const makerAssetFillAmount = orderWithFee.makerAssetAmount.dividedToIntegerBy(2);
+            const ethValue = orderWithFee.takerAssetAmount;
+
+            tx = await forwarderWrapper.marketBuyOrdersWithEthAsync(ordersWithFee, feeOrders, makerAssetFillAmount, {
+                value: ethValue,
+                from: takerAddress,
+            });
+            const takerEthBalanceAfter = await web3Wrapper.getBalanceInWeiAsync(takerAddress);
+            const forwarderEthBalance = await web3Wrapper.getBalanceInWeiAsync(forwarderContract.address);
+            const newBalances = await erc20Wrapper.getBalancesAsync();
+
+            const primaryTakerAssetFillAmount = orderWithFee.takerAssetAmount.dividedToIntegerBy(2);
+            const feeAmount = orderWithFee.takerFee.dividedToIntegerBy(2);
+            const wethSpentOnFeeOrders = ForwarderWrapper.getWethForFeeOrders(feeAmount, feeOrders);
+            const totalEthSpent = primaryTakerAssetFillAmount
+                .plus(wethSpentOnFeeOrders)
+                .plus(gasPrice.times(tx.gasUsed));
+
+            expect(takerEthBalanceAfter).to.be.bignumber.equal(takerEthBalanceBefore.minus(totalEthSpent));
+            expect(newBalances[makerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][defaultMakerAssetAddress].minus(makerAssetFillAmount),
+            );
+            expect(newBalances[takerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[takerAddress][defaultMakerAssetAddress].plus(makerAssetFillAmount),
+            );
+            expect(newBalances[makerAddress][weth.address]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][weth.address].plus(primaryTakerAssetFillAmount).plus(wethSpentOnFeeOrders),
+            );
+            expect(newBalances[forwarderContract.address][weth.address]).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(newBalances[forwarderContract.address][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                constants.ZERO_AMOUNT,
+            );
+            expect(forwarderEthBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+        });
+        it('should buy slightly greater than makerAssetAmount when buying ZRX', async () => {
+            orderWithFee = await orderFactory.newSignedOrderAsync({
+                makerAssetData: assetDataUtils.encodeERC20AssetData(zrxToken.address),
+                takerFee: Web3Wrapper.toBaseUnitAmount(new BigNumber(1), DECIMALS_DEFAULT),
+            });
+            const ordersWithFee = [orderWithFee];
+            const feeOrders: SignedOrder[] = [];
+            const makerAssetFillAmount = orderWithFee.makerAssetAmount.dividedToIntegerBy(2);
+            const ethValue = orderWithFee.takerAssetAmount;
+            tx = await forwarderWrapper.marketBuyOrdersWithEthAsync(ordersWithFee, feeOrders, makerAssetFillAmount, {
+                value: ethValue,
+                from: takerAddress,
+            });
+            const takerEthBalanceAfter = await web3Wrapper.getBalanceInWeiAsync(takerAddress);
+            const forwarderEthBalance = await web3Wrapper.getBalanceInWeiAsync(forwarderContract.address);
+            const newBalances = await erc20Wrapper.getBalancesAsync();
+
+            const primaryTakerAssetFillAmount = ForwarderWrapper.getWethForFeeOrders(
+                makerAssetFillAmount,
+                ordersWithFee,
+            );
+            const totalEthSpent = primaryTakerAssetFillAmount.plus(gasPrice.times(tx.gasUsed));
+            const makerAssetFilledAmount = orderWithFee.makerAssetAmount
+                .times(primaryTakerAssetFillAmount)
+                .dividedToIntegerBy(orderWithFee.takerAssetAmount);
+            const takerFeePaid = orderWithFee.takerFee
+                .times(primaryTakerAssetFillAmount)
+                .dividedToIntegerBy(orderWithFee.takerAssetAmount);
+            const makerFeePaid = orderWithFee.makerFee
+                .times(primaryTakerAssetFillAmount)
+                .dividedToIntegerBy(orderWithFee.takerAssetAmount);
+            const totalZrxPurchased = makerAssetFilledAmount.minus(takerFeePaid);
+            // Up to 1 wei worth of ZRX will be overbought per order
+            const maxOverboughtZrx = new BigNumber(1)
+                .times(orderWithFee.makerAssetAmount)
+                .dividedToIntegerBy(orderWithFee.takerAssetAmount);
+
+            expect(totalZrxPurchased).to.be.bignumber.gte(makerAssetFillAmount);
+            expect(totalZrxPurchased).to.be.bignumber.lte(makerAssetFillAmount.plus(maxOverboughtZrx));
+            expect(takerEthBalanceAfter).to.be.bignumber.equal(takerEthBalanceBefore.minus(totalEthSpent));
+            expect(newBalances[makerAddress][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][zrxToken.address].minus(makerAssetFilledAmount).minus(makerFeePaid),
+            );
+            expect(newBalances[takerAddress][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[takerAddress][zrxToken.address].plus(totalZrxPurchased),
+            );
+            expect(newBalances[makerAddress][weth.address]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][weth.address].plus(primaryTakerAssetFillAmount),
+            );
+            expect(newBalances[forwarderContract.address][weth.address]).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(newBalances[forwarderContract.address][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[forwarderContract.address][zrxToken.address],
+            );
+            expect(forwarderEthBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+        });
+        it('should revert if the amount of ETH sent is too low to fill the makerAssetAmount', async () => {
+            const ordersWithoutFee = [orderWithoutFee];
+            const feeOrders: SignedOrder[] = [];
+            const makerAssetFillAmount = orderWithoutFee.makerAssetAmount.dividedToIntegerBy(2);
+            const ethValue = orderWithoutFee.takerAssetAmount.dividedToIntegerBy(4);
+            return expectTransactionFailedAsync(
+                forwarderWrapper.marketBuyOrdersWithEthAsync(ordersWithoutFee, feeOrders, makerAssetFillAmount, {
+                    value: ethValue,
+                    from: takerAddress,
+                }),
+                RevertReason.CompleteFillFailed,
+            );
+        });
+        it('should buy an ERC721 asset from a single order', async () => {
+            const makerAssetId = erc721MakerAssetIds[0];
+            orderWithoutFee = await orderFactory.newSignedOrderAsync({
+                makerAssetAmount: new BigNumber(1),
+                makerAssetData: assetDataUtils.encodeERC721AssetData(erc721Token.address, makerAssetId),
+            });
+            const ordersWithoutFee = [orderWithoutFee];
+            const feeOrders: SignedOrder[] = [];
+            const makerAssetFillAmount = new BigNumber(1);
+            const ethValue = orderWithFee.takerAssetAmount;
+
+            tx = await forwarderWrapper.marketBuyOrdersWithEthAsync(ordersWithoutFee, feeOrders, makerAssetFillAmount, {
+                from: takerAddress,
+                value: ethValue,
+            });
+            const takerEthBalanceAfter = await web3Wrapper.getBalanceInWeiAsync(takerAddress);
+            const forwarderEthBalance = await web3Wrapper.getBalanceInWeiAsync(forwarderContract.address);
+            const newOwner = await erc721Token.ownerOf.callAsync(makerAssetId);
+            const newBalances = await erc20Wrapper.getBalancesAsync();
+
+            const primaryTakerAssetFillAmount = ethValue;
+            const totalEthSpent = primaryTakerAssetFillAmount.plus(gasPrice.times(tx.gasUsed));
+            expect(newOwner).to.be.bignumber.equal(takerAddress);
+            expect(takerEthBalanceAfter).to.be.bignumber.equal(takerEthBalanceBefore.minus(totalEthSpent));
+            expect(newBalances[makerAddress][weth.address]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][weth.address].plus(primaryTakerAssetFillAmount),
+            );
+            expect(newBalances[forwarderContract.address][weth.address]).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(newBalances[forwarderContract.address][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                constants.ZERO_AMOUNT,
+            );
+            expect(forwarderEthBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+        });
+        it('should revert if buying an ERC721 asset when later orders contain different makerAssetData', async () => {
+            const makerAssetId = erc721MakerAssetIds[0];
+            orderWithoutFee = await orderFactory.newSignedOrderAsync({
+                makerAssetAmount: new BigNumber(1),
+                makerAssetData: assetDataUtils.encodeERC721AssetData(erc721Token.address, makerAssetId),
+            });
+            const differentMakerAssetDataOrder = await orderFactory.newSignedOrderAsync();
+            const ordersWithoutFee = [orderWithoutFee, differentMakerAssetDataOrder];
+            const feeOrders: SignedOrder[] = [];
+            const makerAssetFillAmount = new BigNumber(1).plus(differentMakerAssetDataOrder.makerAssetAmount);
+            const ethValue = orderWithFee.takerAssetAmount;
+            return expectTransactionFailedAsync(
+                forwarderWrapper.marketBuyOrdersWithEthAsync(ordersWithoutFee, feeOrders, makerAssetFillAmount, {
+                    value: ethValue,
+                    from: takerAddress,
+                }),
+                RevertReason.CompleteFillFailed,
+            );
+        });
+        it('should buy an ERC721 asset and pay ZRX fees from a single fee order', async () => {
+            const makerAssetId = erc721MakerAssetIds[0];
+            orderWithFee = await orderFactory.newSignedOrderAsync({
+                makerAssetAmount: new BigNumber(1),
+                makerAssetData: assetDataUtils.encodeERC721AssetData(erc721Token.address, makerAssetId),
+                takerFee: Web3Wrapper.toBaseUnitAmount(new BigNumber(1), DECIMALS_DEFAULT),
+            });
+            const ordersWithFee = [orderWithFee];
+            const feeOrders = [feeOrder];
+            const makerAssetFillAmount = orderWithFee.makerAssetAmount;
+            const primaryTakerAssetFillAmount = orderWithFee.takerAssetAmount;
+            const feeAmount = orderWithFee.takerFee;
+            const wethSpentOnFeeOrders = ForwarderWrapper.getWethForFeeOrders(feeAmount, feeOrders);
+            const ethValue = primaryTakerAssetFillAmount.plus(wethSpentOnFeeOrders);
+
+            tx = await forwarderWrapper.marketBuyOrdersWithEthAsync(ordersWithFee, feeOrders, makerAssetFillAmount, {
+                value: ethValue,
+                from: takerAddress,
+            });
+            const takerEthBalanceAfter = await web3Wrapper.getBalanceInWeiAsync(takerAddress);
+            const forwarderEthBalance = await web3Wrapper.getBalanceInWeiAsync(forwarderContract.address);
+            const newOwner = await erc721Token.ownerOf.callAsync(makerAssetId);
+            const newBalances = await erc20Wrapper.getBalancesAsync();
+
+            const totalEthSpent = ethValue.plus(gasPrice.times(tx.gasUsed));
+
+            expect(newOwner).to.be.bignumber.equal(takerAddress);
+            expect(takerEthBalanceAfter).to.be.bignumber.equal(takerEthBalanceBefore.minus(totalEthSpent));
+            expect(newBalances[makerAddress][weth.address]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][weth.address].plus(primaryTakerAssetFillAmount).plus(wethSpentOnFeeOrders),
+            );
+            expect(newBalances[forwarderContract.address][weth.address]).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(newBalances[forwarderContract.address][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                constants.ZERO_AMOUNT,
+            );
+            expect(forwarderEthBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+        });
+        it('should buy an ERC721 asset and pay ZRX fees from multiple fee orders', async () => {
+            const makerAssetId = erc721MakerAssetIds[0];
+            orderWithFee = await orderFactory.newSignedOrderAsync({
+                makerAssetAmount: new BigNumber(1),
+                makerAssetData: assetDataUtils.encodeERC721AssetData(erc721Token.address, makerAssetId),
+                takerFee: Web3Wrapper.toBaseUnitAmount(new BigNumber(1), DECIMALS_DEFAULT),
+            });
+            const ordersWithFee = [orderWithFee];
+            const makerAssetData = assetDataUtils.encodeERC20AssetData(zrxToken.address);
+            const makerAssetAmount = orderWithFee.takerFee.dividedToIntegerBy(2);
+            const takerAssetAmount = feeOrder.takerAssetAmount
+                .times(makerAssetAmount)
+                .dividedToIntegerBy(feeOrder.makerAssetAmount);
+
+            const firstFeeOrder = await orderFactory.newSignedOrderAsync({
+                makerAssetData,
+                makerAssetAmount,
+                takerAssetAmount,
+            });
+            const secondFeeOrder = await orderFactory.newSignedOrderAsync({
+                makerAssetData,
+                makerAssetAmount,
+                takerAssetAmount,
+            });
+            const feeOrders = [firstFeeOrder, secondFeeOrder];
+
+            const makerAssetFillAmount = orderWithFee.makerAssetAmount;
+            const primaryTakerAssetFillAmount = orderWithFee.takerAssetAmount;
+            const feeAmount = orderWithFee.takerFee;
+            const wethSpentOnFeeOrders = ForwarderWrapper.getWethForFeeOrders(feeAmount, feeOrders);
+            const ethValue = primaryTakerAssetFillAmount.plus(wethSpentOnFeeOrders);
+
+            tx = await forwarderWrapper.marketBuyOrdersWithEthAsync(ordersWithFee, feeOrders, makerAssetFillAmount, {
+                value: ethValue,
+                from: takerAddress,
+            });
+            const takerEthBalanceAfter = await web3Wrapper.getBalanceInWeiAsync(takerAddress);
+            const forwarderEthBalance = await web3Wrapper.getBalanceInWeiAsync(forwarderContract.address);
+            const newOwner = await erc721Token.ownerOf.callAsync(makerAssetId);
+            const newBalances = await erc20Wrapper.getBalancesAsync();
+
+            const totalEthSpent = ethValue.plus(gasPrice.times(tx.gasUsed));
+
+            expect(newOwner).to.be.bignumber.equal(takerAddress);
+            expect(takerEthBalanceAfter).to.be.bignumber.equal(takerEthBalanceBefore.minus(totalEthSpent));
+            expect(newBalances[makerAddress][weth.address]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][weth.address].plus(primaryTakerAssetFillAmount).plus(wethSpentOnFeeOrders),
+            );
+            expect(newBalances[forwarderContract.address][weth.address]).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(newBalances[forwarderContract.address][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                constants.ZERO_AMOUNT,
+            );
+            expect(forwarderEthBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+        });
+        it('Should buy slightly greater MakerAsset when exchange rate is rounded', async () => {
+            // The 0x Protocol contracts round the exchange rate in favor of the Maker.
+            // In this case, the taker must round up how much they're going to spend, which
+            // in turn increases the amount of MakerAsset being purchased.
+            // Example:
+            //  The taker wants to buy 5 units of the MakerAsset at a rate of 3M/2T.
+            //  For every 2 units of TakerAsset, the taker will receive 3 units of MakerAsset.
+            //  To purchase 5 units, the taker must spend 10/3 = 3.33 units of TakerAssset.
+            //  However, the Taker can only spend whole units.
+            //  Spending floor(10/3) = 3 units will yield a profit of Floor(3*3/2) = Floor(4.5) = 4 units of MakerAsset.
+            //  Spending ceil(10/3) = 4 units will yield a profit of Floor(4*3/2) = 6 units of MakerAsset.
+            //
+            //  The forwarding contract will opt for the second option, which overbuys, to ensure the taker
+            //  receives at least the amount of MakerAsset they requested.
+            //
+            // Construct test case using values from example above
+            orderWithoutFee = await orderFactory.newSignedOrderAsync({
+                makerAssetAmount: new BigNumber('30'),
+                takerAssetAmount: new BigNumber('20'),
+                makerAssetData: assetDataUtils.encodeERC20AssetData(erc20TokenA.address),
+                takerAssetData: assetDataUtils.encodeERC20AssetData(weth.address),
+                makerFee: new BigNumber(0),
+                takerFee: new BigNumber(0),
+            });
+            const ordersWithoutFee = [orderWithoutFee];
+            const feeOrders: SignedOrder[] = [];
+            const desiredMakerAssetFillAmount = new BigNumber('5');
+            const makerAssetFillAmount = new BigNumber('6');
+            const ethValue = new BigNumber('4');
+            // Execute test case
+            tx = await forwarderWrapper.marketBuyOrdersWithEthAsync(
+                ordersWithoutFee,
+                feeOrders,
+                desiredMakerAssetFillAmount,
+                {
+                    value: ethValue,
+                    from: takerAddress,
+                },
+            );
+            // Fetch end balances and construct expected outputs
+            const takerEthBalanceAfter = await web3Wrapper.getBalanceInWeiAsync(takerAddress);
+            const forwarderEthBalance = await web3Wrapper.getBalanceInWeiAsync(forwarderContract.address);
+            const newBalances = await erc20Wrapper.getBalancesAsync();
+            const primaryTakerAssetFillAmount = ethValue;
+            const totalEthSpent = primaryTakerAssetFillAmount.plus(gasPrice.times(tx.gasUsed));
+            // Validate test case
+            expect(makerAssetFillAmount).to.be.bignumber.greaterThan(desiredMakerAssetFillAmount);
+            expect(takerEthBalanceAfter).to.be.bignumber.equal(takerEthBalanceBefore.minus(totalEthSpent));
+            expect(newBalances[makerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][defaultMakerAssetAddress].minus(makerAssetFillAmount),
+            );
+            expect(newBalances[takerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[takerAddress][defaultMakerAssetAddress].plus(makerAssetFillAmount),
+            );
+            expect(newBalances[makerAddress][weth.address]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][weth.address].plus(primaryTakerAssetFillAmount),
+            );
+            expect(newBalances[forwarderContract.address][weth.address]).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(newBalances[forwarderContract.address][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                constants.ZERO_AMOUNT,
+            );
+            expect(forwarderEthBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+        });
+        it('Should buy slightly greater MakerAsset when exchange rate is rounded, and MakerAsset is ZRX', async () => {
+            // See the test case above for a detailed description of this case.
+            // The difference here is that the MakerAsset is ZRX. We expect the same result as above,
+            // but this tests a different code path.
+            //
+            // Construct test case using values from example above
+            orderWithoutFee = await orderFactory.newSignedOrderAsync({
+                makerAssetAmount: new BigNumber('30'),
+                takerAssetAmount: new BigNumber('20'),
+                makerAssetData: zrxAssetData,
+                takerAssetData: assetDataUtils.encodeERC20AssetData(weth.address),
+                makerFee: new BigNumber(0),
+                takerFee: new BigNumber(0),
+            });
+            const ordersWithoutFee = [orderWithoutFee];
+            const feeOrders: SignedOrder[] = [];
+            const desiredMakerAssetFillAmount = new BigNumber('5');
+            const makerAssetFillAmount = new BigNumber('6');
+            const ethValue = new BigNumber('4');
+            // Execute test case
+            tx = await forwarderWrapper.marketBuyOrdersWithEthAsync(
+                ordersWithoutFee,
+                feeOrders,
+                desiredMakerAssetFillAmount,
+                {
+                    value: ethValue,
+                    from: takerAddress,
+                },
+            );
+            // Fetch end balances and construct expected outputs
+            const takerEthBalanceAfter = await web3Wrapper.getBalanceInWeiAsync(takerAddress);
+            const forwarderEthBalance = await web3Wrapper.getBalanceInWeiAsync(forwarderContract.address);
+            const newBalances = await erc20Wrapper.getBalancesAsync();
+            const primaryTakerAssetFillAmount = ethValue;
+            const totalEthSpent = primaryTakerAssetFillAmount.plus(gasPrice.times(tx.gasUsed));
+            // Validate test case
+            expect(makerAssetFillAmount).to.be.bignumber.greaterThan(desiredMakerAssetFillAmount);
+            expect(takerEthBalanceAfter).to.be.bignumber.equal(takerEthBalanceBefore.minus(totalEthSpent));
+            expect(newBalances[makerAddress][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][zrxToken.address].minus(makerAssetFillAmount),
+            );
+            expect(newBalances[takerAddress][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[takerAddress][zrxToken.address].plus(makerAssetFillAmount),
+            );
+            expect(newBalances[makerAddress][weth.address]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][weth.address].plus(primaryTakerAssetFillAmount),
+            );
+            expect(newBalances[forwarderContract.address][weth.address]).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(forwarderEthBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+        });
+        it('Should buy slightly greater MakerAsset when exchange rate is rounded (Regression Test)', async () => {
+            // Order taken from a transaction on mainnet that failed due to a rounding error.
+            orderWithoutFee = await orderFactory.newSignedOrderAsync({
+                makerAssetAmount: new BigNumber('268166666666666666666'),
+                takerAssetAmount: new BigNumber('219090625878836371'),
+                makerAssetData: assetDataUtils.encodeERC20AssetData(erc20TokenA.address),
+                takerAssetData: assetDataUtils.encodeERC20AssetData(weth.address),
+                makerFee: new BigNumber(0),
+                takerFee: new BigNumber(0),
+            });
+            const ordersWithoutFee = [orderWithoutFee];
+            const feeOrders: SignedOrder[] = [];
+            // The taker will receive more than the desired amount of makerAsset due to rounding
+            const desiredMakerAssetFillAmount = new BigNumber('5000000000000000000');
+            const ethValue = new BigNumber('4084971271824171');
+            const makerAssetFillAmount = ethValue
+                .times(orderWithoutFee.makerAssetAmount)
+                .dividedToIntegerBy(orderWithoutFee.takerAssetAmount);
+            // Execute test case
+            tx = await forwarderWrapper.marketBuyOrdersWithEthAsync(
+                ordersWithoutFee,
+                feeOrders,
+                desiredMakerAssetFillAmount,
+                {
+                    value: ethValue,
+                    from: takerAddress,
+                },
+            );
+            // Fetch end balances and construct expected outputs
+            const takerEthBalanceAfter = await web3Wrapper.getBalanceInWeiAsync(takerAddress);
+            const forwarderEthBalance = await web3Wrapper.getBalanceInWeiAsync(forwarderContract.address);
+            const newBalances = await erc20Wrapper.getBalancesAsync();
+            const primaryTakerAssetFillAmount = ethValue;
+            const totalEthSpent = primaryTakerAssetFillAmount.plus(gasPrice.times(tx.gasUsed));
+            // Validate test case
+            expect(makerAssetFillAmount).to.be.bignumber.greaterThan(desiredMakerAssetFillAmount);
+            expect(takerEthBalanceAfter).to.be.bignumber.equal(takerEthBalanceBefore.minus(totalEthSpent));
+            expect(newBalances[makerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][defaultMakerAssetAddress].minus(makerAssetFillAmount),
+            );
+            expect(newBalances[takerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[takerAddress][defaultMakerAssetAddress].plus(makerAssetFillAmount),
+            );
+            expect(newBalances[makerAddress][weth.address]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][weth.address].plus(primaryTakerAssetFillAmount),
+            );
+            expect(newBalances[forwarderContract.address][weth.address]).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(newBalances[forwarderContract.address][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                constants.ZERO_AMOUNT,
+            );
+            expect(forwarderEthBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+        });
+        it('Should buy slightly greater MakerAsset when exchange rate is rounded, and MakerAsset is ZRX (Regression Test)', async () => {
+            // Order taken from a transaction on mainnet that failed due to a rounding error.
+            orderWithoutFee = await orderFactory.newSignedOrderAsync({
+                makerAssetAmount: new BigNumber('268166666666666666666'),
+                takerAssetAmount: new BigNumber('219090625878836371'),
+                makerAssetData: zrxAssetData,
+                takerAssetData: assetDataUtils.encodeERC20AssetData(weth.address),
+                makerFee: new BigNumber(0),
+                takerFee: new BigNumber(0),
+            });
+            const ordersWithoutFee = [orderWithoutFee];
+            const feeOrders: SignedOrder[] = [];
+            // The taker will receive more than the desired amount of makerAsset due to rounding
+            const desiredMakerAssetFillAmount = new BigNumber('5000000000000000000');
+            const ethValue = new BigNumber('4084971271824171');
+            const makerAssetFillAmount = ethValue
+                .times(orderWithoutFee.makerAssetAmount)
+                .dividedToIntegerBy(orderWithoutFee.takerAssetAmount);
+            // Execute test case
+            tx = await forwarderWrapper.marketBuyOrdersWithEthAsync(
+                ordersWithoutFee,
+                feeOrders,
+                desiredMakerAssetFillAmount,
+                {
+                    value: ethValue,
+                    from: takerAddress,
+                },
+            );
+            // Fetch end balances and construct expected outputs
+            const takerEthBalanceAfter = await web3Wrapper.getBalanceInWeiAsync(takerAddress);
+            const forwarderEthBalance = await web3Wrapper.getBalanceInWeiAsync(forwarderContract.address);
+            const newBalances = await erc20Wrapper.getBalancesAsync();
+            const primaryTakerAssetFillAmount = ethValue;
+            const totalEthSpent = primaryTakerAssetFillAmount.plus(gasPrice.times(tx.gasUsed));
+            // Validate test case
+            expect(makerAssetFillAmount).to.be.bignumber.greaterThan(desiredMakerAssetFillAmount);
+            expect(takerEthBalanceAfter).to.be.bignumber.equal(takerEthBalanceBefore.minus(totalEthSpent));
+            expect(newBalances[makerAddress][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][zrxToken.address].minus(makerAssetFillAmount),
+            );
+            expect(newBalances[takerAddress][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[takerAddress][zrxToken.address].plus(makerAssetFillAmount),
+            );
+            expect(newBalances[makerAddress][weth.address]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][weth.address].plus(primaryTakerAssetFillAmount),
+            );
+            expect(newBalances[forwarderContract.address][weth.address]).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(forwarderEthBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+        });
+        it('Should buy correct MakerAsset when exchange rate is NOT rounded, and MakerAsset is ZRX (Regression Test)', async () => {
+            // An extra unit of TakerAsset was sent to the exchange contract to account for rounding errors, in Forwarder v1.
+            // Specifically, the takerFillAmount was calculated using Floor(desiredMakerAmount * exchangeRate) + 1
+            // We have since changed this to be Ceil(desiredMakerAmount * exchangeRate)
+            // These calculations produce different results when `desiredMakerAmount * exchangeRate` is an integer.
+            //
+            // This test verifies that `ceil` is sufficient:
+            //  Let TakerAssetAmount = MakerAssetAmount * 2
+            //  -> exchangeRate = TakerAssetAmount / MakerAssetAmount = (2*MakerAssetAmount)/MakerAssetAmount = 2
+            //  .: desiredMakerAmount * exchangeRate is an integer.
+            //
+            // Construct test case using values from example above
+            orderWithoutFee = await orderFactory.newSignedOrderAsync({
+                makerAssetAmount: new BigNumber('30'),
+                takerAssetAmount: new BigNumber('60'),
+                makerAssetData: zrxAssetData,
+                takerAssetData: assetDataUtils.encodeERC20AssetData(weth.address),
+                makerFee: new BigNumber(0),
+                takerFee: new BigNumber(0),
+            });
+            const ordersWithoutFee = [orderWithoutFee];
+            const feeOrders: SignedOrder[] = [];
+            const makerAssetFillAmount = new BigNumber('5');
+            const ethValue = new BigNumber('10');
+            // Execute test case
+            tx = await forwarderWrapper.marketBuyOrdersWithEthAsync(ordersWithoutFee, feeOrders, makerAssetFillAmount, {
+                value: ethValue,
+                from: takerAddress,
+            });
+            // Fetch end balances and construct expected outputs
+            const takerEthBalanceAfter = await web3Wrapper.getBalanceInWeiAsync(takerAddress);
+            const forwarderEthBalance = await web3Wrapper.getBalanceInWeiAsync(forwarderContract.address);
+            const newBalances = await erc20Wrapper.getBalancesAsync();
+            const primaryTakerAssetFillAmount = ethValue;
+            const totalEthSpent = primaryTakerAssetFillAmount.plus(gasPrice.times(tx.gasUsed));
+            // Validate test case
+            expect(takerEthBalanceAfter).to.be.bignumber.equal(takerEthBalanceBefore.minus(totalEthSpent));
+            expect(newBalances[makerAddress][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][zrxToken.address].minus(makerAssetFillAmount),
+            );
+            expect(newBalances[takerAddress][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[takerAddress][zrxToken.address].plus(makerAssetFillAmount),
+            );
+            expect(newBalances[makerAddress][weth.address]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][weth.address].plus(primaryTakerAssetFillAmount),
+            );
+            expect(newBalances[forwarderContract.address][weth.address]).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(forwarderEthBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+        });
+    });
+    describe('marketBuyOrdersWithEth with extra fees', () => {
+        it('should buy an asset and send fee to feeRecipient', async () => {
+            const ordersWithoutFee = [orderWithoutFee];
+            const feeOrders: SignedOrder[] = [];
+            const makerAssetFillAmount = orderWithoutFee.makerAssetAmount.dividedToIntegerBy(2);
+            const ethValue = orderWithoutFee.takerAssetAmount;
+
+            const baseFeePercentage = 2;
+            feePercentage = ForwarderWrapper.getPercentageOfValue(constants.PERCENTAGE_DENOMINATOR, baseFeePercentage);
+            const feeRecipientEthBalanceBefore = await web3Wrapper.getBalanceInWeiAsync(feeRecipientAddress);
+            tx = await forwarderWrapper.marketBuyOrdersWithEthAsync(
+                ordersWithoutFee,
+                feeOrders,
+                makerAssetFillAmount,
+                {
+                    value: ethValue,
+                    from: takerAddress,
+                },
+                { feePercentage, feeRecipient: feeRecipientAddress },
+            );
+            const takerEthBalanceAfter = await web3Wrapper.getBalanceInWeiAsync(takerAddress);
+            const forwarderEthBalance = await web3Wrapper.getBalanceInWeiAsync(forwarderContract.address);
+            const feeRecipientEthBalanceAfter = await web3Wrapper.getBalanceInWeiAsync(feeRecipientAddress);
+            const newBalances = await erc20Wrapper.getBalancesAsync();
+
+            const primaryTakerAssetFillAmount = orderWithoutFee.takerAssetAmount.dividedToIntegerBy(2);
+            const ethSpentOnFee = ForwarderWrapper.getPercentageOfValue(primaryTakerAssetFillAmount, baseFeePercentage);
+            const totalEthSpent = primaryTakerAssetFillAmount.plus(ethSpentOnFee).plus(gasPrice.times(tx.gasUsed));
+
+            expect(feeRecipientEthBalanceAfter).to.be.bignumber.equal(feeRecipientEthBalanceBefore.plus(ethSpentOnFee));
+            expect(takerEthBalanceAfter).to.be.bignumber.equal(takerEthBalanceBefore.minus(totalEthSpent));
+            expect(newBalances[makerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][defaultMakerAssetAddress].minus(makerAssetFillAmount),
+            );
+            expect(newBalances[takerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[takerAddress][defaultMakerAssetAddress].plus(makerAssetFillAmount),
+            );
+            expect(newBalances[makerAddress][weth.address]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][weth.address].plus(primaryTakerAssetFillAmount),
+            );
+            expect(newBalances[forwarderContract.address][weth.address]).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(newBalances[forwarderContract.address][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                constants.ZERO_AMOUNT,
+            );
+            expect(forwarderEthBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+        });
+        it('should fail if the fee is set too high', async () => {
+            const ordersWithoutFee = [orderWithoutFee];
+            const feeOrders: SignedOrder[] = [];
+            const makerAssetFillAmount = orderWithoutFee.makerAssetAmount.dividedToIntegerBy(2);
+            const ethValue = orderWithoutFee.takerAssetAmount;
+
+            const baseFeePercentage = 6;
+            feePercentage = ForwarderWrapper.getPercentageOfValue(constants.PERCENTAGE_DENOMINATOR, baseFeePercentage);
+            await expectTransactionFailedAsync(
+                forwarderWrapper.marketBuyOrdersWithEthAsync(
+                    ordersWithoutFee,
+                    feeOrders,
+                    makerAssetFillAmount,
+                    {
+                        value: ethValue,
+                        from: takerAddress,
+                    },
+                    { feePercentage, feeRecipient: feeRecipientAddress },
+                ),
+                RevertReason.FeePercentageTooLarge,
+            );
+        });
+        it('should fail if there is not enough ETH remaining to pay the fee', async () => {
+            const ordersWithoutFee = [orderWithoutFee];
+            const feeOrders: SignedOrder[] = [];
+            const makerAssetFillAmount = orderWithoutFee.makerAssetAmount.dividedToIntegerBy(2);
+            const ethValue = orderWithoutFee.takerAssetAmount.dividedToIntegerBy(2);
+
+            const baseFeePercentage = 2;
+            feePercentage = ForwarderWrapper.getPercentageOfValue(constants.PERCENTAGE_DENOMINATOR, baseFeePercentage);
+            await expectTransactionFailedAsync(
+                forwarderWrapper.marketBuyOrdersWithEthAsync(
+                    ordersWithoutFee,
+                    feeOrders,
+                    makerAssetFillAmount,
+                    {
+                        value: ethValue,
+                        from: takerAddress,
+                    },
+                    { feePercentage, feeRecipient: feeRecipientAddress },
+                ),
+                RevertReason.InsufficientEthRemaining,
+            );
+        });
+    });
+    describe('withdrawAsset', () => {
+        it('should allow owner to withdraw ERC20 tokens', async () => {
+            const zrxWithdrawAmount = erc20Balances[forwarderContract.address][zrxToken.address];
+            await forwarderWrapper.withdrawAssetAsync(zrxAssetData, zrxWithdrawAmount, { from: owner });
+            const newBalances = await erc20Wrapper.getBalancesAsync();
+            expect(newBalances[owner][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[owner][zrxToken.address].plus(zrxWithdrawAmount),
+            );
+            expect(newBalances[forwarderContract.address][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[forwarderContract.address][zrxToken.address].minus(zrxWithdrawAmount),
+            );
+        });
+        it('should revert if not called by owner', async () => {
+            const zrxWithdrawAmount = erc20Balances[forwarderContract.address][zrxToken.address];
+            await expectTransactionFailedAsync(
+                forwarderWrapper.withdrawAssetAsync(zrxAssetData, zrxWithdrawAmount, { from: makerAddress }),
+                RevertReason.OnlyContractOwner,
+            );
+        });
+    });
+});
+// tslint:disable:max-file-line-count
+// tslint:enable:no-unnecessary-type-assertion
diff --git a/contracts/extensions/test/extensions/order_validator.ts b/contracts/extensions/test/extensions/order_validator.ts
new file mode 100644
index 000000000..9a1dc0636
--- /dev/null
+++ b/contracts/extensions/test/extensions/order_validator.ts
@@ -0,0 +1,609 @@
+import {
+    artifacts as coreArtifacts,
+    ERC20ProxyContract,
+    ERC20Wrapper,
+    ERC721ProxyContract,
+    ERC721Wrapper,
+    ExchangeContract,
+    ExchangeWrapper,
+} from '@0x/contracts-core';
+import {
+    chaiSetup,
+    constants,
+    OrderFactory,
+    OrderStatus,
+    provider,
+    txDefaults,
+    web3Wrapper,
+} from '@0x/contracts-test-utils';
+import { DummyERC20TokenContract, DummyERC721TokenContract } from '@0x/contracts-tokens';
+import { BlockchainLifecycle } from '@0x/dev-utils';
+import { assetDataUtils, orderHashUtils } from '@0x/order-utils';
+import { SignedOrder } from '@0x/types';
+import { BigNumber } from '@0x/utils';
+import * as chai from 'chai';
+import * as _ from 'lodash';
+
+import { OrderValidatorContract } from '../../generated-wrappers/order_validator';
+import { artifacts } from '../../src/artifacts';
+
+chaiSetup.configure();
+const expect = chai.expect;
+const blockchainLifecycle = new BlockchainLifecycle(web3Wrapper);
+
+describe('OrderValidator', () => {
+    let makerAddress: string;
+    let owner: string;
+    let takerAddress: string;
+    let erc20AssetData: string;
+    let erc721AssetData: string;
+
+    let erc20Token: DummyERC20TokenContract;
+    let zrxToken: DummyERC20TokenContract;
+    let erc721Token: DummyERC721TokenContract;
+    let exchange: ExchangeContract;
+    let orderValidator: OrderValidatorContract;
+    let erc20Proxy: ERC20ProxyContract;
+    let erc721Proxy: ERC721ProxyContract;
+
+    let signedOrder: SignedOrder;
+    let signedOrder2: SignedOrder;
+    let orderFactory: OrderFactory;
+
+    const tokenId = new BigNumber(123456789);
+    const tokenId2 = new BigNumber(987654321);
+    const ERC721_BALANCE = new BigNumber(1);
+    const ERC721_ALLOWANCE = new BigNumber(1);
+
+    before(async () => {
+        await blockchainLifecycle.startAsync();
+    });
+    after(async () => {
+        await blockchainLifecycle.revertAsync();
+    });
+
+    before(async () => {
+        const accounts = await web3Wrapper.getAvailableAddressesAsync();
+        const usedAddresses = ([owner, makerAddress, takerAddress] = _.slice(accounts, 0, 3));
+
+        const erc20Wrapper = new ERC20Wrapper(provider, usedAddresses, owner);
+        const erc721Wrapper = new ERC721Wrapper(provider, usedAddresses, owner);
+
+        const numDummyErc20ToDeploy = 2;
+        [erc20Token, zrxToken] = await erc20Wrapper.deployDummyTokensAsync(
+            numDummyErc20ToDeploy,
+            constants.DUMMY_TOKEN_DECIMALS,
+        );
+        erc20Proxy = await erc20Wrapper.deployProxyAsync();
+
+        [erc721Token] = await erc721Wrapper.deployDummyTokensAsync();
+        erc721Proxy = await erc721Wrapper.deployProxyAsync();
+
+        const zrxAssetData = assetDataUtils.encodeERC20AssetData(zrxToken.address);
+        exchange = await ExchangeContract.deployFrom0xArtifactAsync(
+            coreArtifacts.Exchange,
+            provider,
+            txDefaults,
+            zrxAssetData,
+        );
+        const exchangeWrapper = new ExchangeWrapper(exchange, provider);
+        await exchangeWrapper.registerAssetProxyAsync(erc20Proxy.address, owner);
+        await exchangeWrapper.registerAssetProxyAsync(erc721Proxy.address, owner);
+
+        orderValidator = await OrderValidatorContract.deployFrom0xArtifactAsync(
+            artifacts.OrderValidator,
+            provider,
+            txDefaults,
+            exchange.address,
+            zrxAssetData,
+        );
+
+        erc20AssetData = assetDataUtils.encodeERC20AssetData(erc20Token.address);
+        erc721AssetData = assetDataUtils.encodeERC721AssetData(erc721Token.address, tokenId);
+        const defaultOrderParams = {
+            ...constants.STATIC_ORDER_PARAMS,
+            exchangeAddress: exchange.address,
+            makerAddress,
+            feeRecipientAddress: constants.NULL_ADDRESS,
+            makerAssetData: erc20AssetData,
+            takerAssetData: erc721AssetData,
+        };
+        const privateKey = constants.TESTRPC_PRIVATE_KEYS[accounts.indexOf(makerAddress)];
+        orderFactory = new OrderFactory(privateKey, defaultOrderParams);
+    });
+
+    beforeEach(async () => {
+        await blockchainLifecycle.startAsync();
+    });
+    afterEach(async () => {
+        await blockchainLifecycle.revertAsync();
+    });
+
+    describe('getBalanceAndAllowance', () => {
+        describe('getERC721TokenOwner', async () => {
+            it('should return the null address when tokenId is not owned', async () => {
+                const tokenOwner = await orderValidator.getERC721TokenOwner.callAsync(makerAddress, tokenId);
+                expect(tokenOwner).to.be.equal(constants.NULL_ADDRESS);
+            });
+            it('should return the owner address when tokenId is owned', async () => {
+                await web3Wrapper.awaitTransactionSuccessAsync(
+                    await erc721Token.mint.sendTransactionAsync(makerAddress, tokenId),
+                    constants.AWAIT_TRANSACTION_MINED_MS,
+                );
+                const tokenOwner = await orderValidator.getERC721TokenOwner.callAsync(erc721Token.address, tokenId);
+                expect(tokenOwner).to.be.equal(makerAddress);
+            });
+        });
+        describe('ERC20 assetData', () => {
+            it('should return the correct balances and allowances when both values are 0', async () => {
+                const [newBalance, newAllowance] = await orderValidator.getBalanceAndAllowance.callAsync(
+                    makerAddress,
+                    erc20AssetData,
+                );
+                expect(constants.ZERO_AMOUNT).to.be.bignumber.equal(newBalance);
+                expect(constants.ZERO_AMOUNT).to.be.bignumber.equal(newAllowance);
+            });
+            it('should return the correct balance and allowance when both values are non-zero', async () => {
+                const balance = new BigNumber(123);
+                const allowance = new BigNumber(456);
+                await web3Wrapper.awaitTransactionSuccessAsync(
+                    await erc20Token.setBalance.sendTransactionAsync(makerAddress, balance),
+                    constants.AWAIT_TRANSACTION_MINED_MS,
+                );
+                await web3Wrapper.awaitTransactionSuccessAsync(
+                    await erc20Token.approve.sendTransactionAsync(erc20Proxy.address, allowance, {
+                        from: makerAddress,
+                    }),
+                    constants.AWAIT_TRANSACTION_MINED_MS,
+                );
+                const [newBalance, newAllowance] = await orderValidator.getBalanceAndAllowance.callAsync(
+                    makerAddress,
+                    erc20AssetData,
+                );
+                expect(balance).to.be.bignumber.equal(newBalance);
+                expect(allowance).to.be.bignumber.equal(newAllowance);
+            });
+        });
+        describe('ERC721 assetData', () => {
+            it('should return a balance of 0 when the tokenId is not owned by target', async () => {
+                const [newBalance] = await orderValidator.getBalanceAndAllowance.callAsync(
+                    makerAddress,
+                    erc721AssetData,
+                );
+                expect(newBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            });
+            it('should return an allowance of 0 when no approval is set', async () => {
+                const [, newAllowance] = await orderValidator.getBalanceAndAllowance.callAsync(
+                    makerAddress,
+                    erc721AssetData,
+                );
+                expect(newAllowance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            });
+            it('should return a balance of 1 when the tokenId is owned by target', async () => {
+                await web3Wrapper.awaitTransactionSuccessAsync(
+                    await erc721Token.mint.sendTransactionAsync(makerAddress, tokenId),
+                    constants.AWAIT_TRANSACTION_MINED_MS,
+                );
+                const [newBalance] = await orderValidator.getBalanceAndAllowance.callAsync(
+                    makerAddress,
+                    erc721AssetData,
+                );
+                expect(newBalance).to.be.bignumber.equal(ERC721_BALANCE);
+            });
+            it('should return an allowance of 1 when ERC721Proxy is approved for all', async () => {
+                const isApproved = true;
+                await web3Wrapper.awaitTransactionSuccessAsync(
+                    await erc721Token.setApprovalForAll.sendTransactionAsync(erc721Proxy.address, isApproved, {
+                        from: makerAddress,
+                    }),
+                    constants.AWAIT_TRANSACTION_MINED_MS,
+                );
+                const [, newAllowance] = await orderValidator.getBalanceAndAllowance.callAsync(
+                    makerAddress,
+                    erc721AssetData,
+                );
+                expect(newAllowance).to.be.bignumber.equal(ERC721_ALLOWANCE);
+            });
+            it('should return an allowance of 0 when ERC721Proxy is approved for specific tokenId', async () => {
+                await web3Wrapper.awaitTransactionSuccessAsync(
+                    await erc721Token.mint.sendTransactionAsync(makerAddress, tokenId),
+                    constants.AWAIT_TRANSACTION_MINED_MS,
+                );
+                await web3Wrapper.awaitTransactionSuccessAsync(
+                    await erc721Token.approve.sendTransactionAsync(erc721Proxy.address, tokenId, {
+                        from: makerAddress,
+                    }),
+                    constants.AWAIT_TRANSACTION_MINED_MS,
+                );
+                const [, newAllowance] = await orderValidator.getBalanceAndAllowance.callAsync(
+                    makerAddress,
+                    erc721AssetData,
+                );
+                expect(newAllowance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            });
+        });
+    });
+    describe('getBalancesAndAllowances', () => {
+        it('should return the correct balances and allowances when all values are 0', async () => {
+            const [
+                [erc20Balance, erc721Balance],
+                [erc20Allowance, erc721Allowance],
+            ] = await orderValidator.getBalancesAndAllowances.callAsync(makerAddress, [
+                erc20AssetData,
+                erc721AssetData,
+            ]);
+            expect(erc20Balance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(erc721Balance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(erc20Allowance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(erc721Allowance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+        });
+        it('should return the correct balances and allowances when balances and allowances are non-zero', async () => {
+            const balance = new BigNumber(123);
+            const allowance = new BigNumber(456);
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await erc20Token.setBalance.sendTransactionAsync(makerAddress, balance),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await erc20Token.approve.sendTransactionAsync(erc20Proxy.address, allowance, {
+                    from: makerAddress,
+                }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await erc721Token.mint.sendTransactionAsync(makerAddress, tokenId),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            const isApproved = true;
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await erc721Token.setApprovalForAll.sendTransactionAsync(erc721Proxy.address, isApproved, {
+                    from: makerAddress,
+                }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            const [
+                [erc20Balance, erc721Balance],
+                [erc20Allowance, erc721Allowance],
+            ] = await orderValidator.getBalancesAndAllowances.callAsync(makerAddress, [
+                erc20AssetData,
+                erc721AssetData,
+            ]);
+            expect(erc20Balance).to.be.bignumber.equal(balance);
+            expect(erc721Balance).to.be.bignumber.equal(ERC721_BALANCE);
+            expect(erc20Allowance).to.be.bignumber.equal(allowance);
+            expect(erc721Allowance).to.be.bignumber.equal(ERC721_ALLOWANCE);
+        });
+    });
+    describe('getTraderInfo', () => {
+        beforeEach(async () => {
+            signedOrder = await orderFactory.newSignedOrderAsync();
+        });
+        it('should return the correct info when no balances or allowances are set', async () => {
+            const traderInfo = await orderValidator.getTraderInfo.callAsync(signedOrder, takerAddress);
+            expect(traderInfo.makerBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo.makerAllowance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo.takerBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo.takerAllowance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo.makerZrxBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo.makerZrxAllowance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo.takerZrxBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo.takerZrxAllowance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+        });
+        it('should return the correct info when balances and allowances are set', async () => {
+            const makerBalance = new BigNumber(123);
+            const makerAllowance = new BigNumber(456);
+            const makerZrxBalance = new BigNumber(789);
+            const takerZrxAllowance = new BigNumber(987);
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await erc20Token.setBalance.sendTransactionAsync(makerAddress, makerBalance),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await erc20Token.approve.sendTransactionAsync(erc20Proxy.address, makerAllowance, {
+                    from: makerAddress,
+                }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await zrxToken.setBalance.sendTransactionAsync(makerAddress, makerZrxBalance),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await zrxToken.approve.sendTransactionAsync(erc20Proxy.address, takerZrxAllowance, {
+                    from: takerAddress,
+                }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await erc721Token.mint.sendTransactionAsync(takerAddress, tokenId),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            const isApproved = true;
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await erc721Token.setApprovalForAll.sendTransactionAsync(erc721Proxy.address, isApproved, {
+                    from: takerAddress,
+                }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            const traderInfo = await orderValidator.getTraderInfo.callAsync(signedOrder, takerAddress);
+            expect(traderInfo.makerBalance).to.be.bignumber.equal(makerBalance);
+            expect(traderInfo.makerAllowance).to.be.bignumber.equal(makerAllowance);
+            expect(traderInfo.takerBalance).to.be.bignumber.equal(ERC721_BALANCE);
+            expect(traderInfo.takerAllowance).to.be.bignumber.equal(ERC721_ALLOWANCE);
+            expect(traderInfo.makerZrxBalance).to.be.bignumber.equal(makerZrxBalance);
+            expect(traderInfo.makerZrxAllowance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo.takerZrxBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo.takerZrxAllowance).to.be.bignumber.equal(takerZrxAllowance);
+        });
+    });
+    describe('getTradersInfo', () => {
+        beforeEach(async () => {
+            signedOrder = await orderFactory.newSignedOrderAsync();
+            signedOrder2 = await orderFactory.newSignedOrderAsync({
+                takerAssetData: assetDataUtils.encodeERC721AssetData(erc721Token.address, tokenId2),
+            });
+        });
+        it('should return the correct info when no balances or allowances have been set', async () => {
+            const orders = [signedOrder, signedOrder2];
+            const takers = [takerAddress, takerAddress];
+            const [traderInfo1, traderInfo2] = await orderValidator.getTradersInfo.callAsync(orders, takers);
+            expect(traderInfo1.makerBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo1.makerAllowance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo1.takerBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo1.takerAllowance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo1.makerZrxBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo1.makerZrxAllowance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo1.takerZrxBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo1.takerZrxAllowance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo2.makerBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo2.makerAllowance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo2.takerBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo2.takerAllowance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo2.makerZrxBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo2.makerZrxAllowance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo2.takerZrxBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo2.takerZrxAllowance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+        });
+        it('should return the correct info when balances and allowances are set', async () => {
+            const makerBalance = new BigNumber(123);
+            const makerAllowance = new BigNumber(456);
+            const makerZrxBalance = new BigNumber(789);
+            const takerZrxAllowance = new BigNumber(987);
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await erc20Token.setBalance.sendTransactionAsync(makerAddress, makerBalance),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await erc20Token.approve.sendTransactionAsync(erc20Proxy.address, makerAllowance, {
+                    from: makerAddress,
+                }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await zrxToken.setBalance.sendTransactionAsync(makerAddress, makerZrxBalance),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await zrxToken.approve.sendTransactionAsync(erc20Proxy.address, takerZrxAllowance, {
+                    from: takerAddress,
+                }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            const isApproved = true;
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await erc721Token.setApprovalForAll.sendTransactionAsync(erc721Proxy.address, isApproved, {
+                    from: takerAddress,
+                }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await erc721Token.mint.sendTransactionAsync(takerAddress, tokenId2),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            const orders = [signedOrder, signedOrder2];
+            const takers = [takerAddress, takerAddress];
+            const [traderInfo1, traderInfo2] = await orderValidator.getTradersInfo.callAsync(orders, takers);
+
+            expect(traderInfo1.makerBalance).to.be.bignumber.equal(makerBalance);
+            expect(traderInfo1.makerAllowance).to.be.bignumber.equal(makerAllowance);
+            expect(traderInfo1.takerBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo1.takerAllowance).to.be.bignumber.equal(ERC721_ALLOWANCE);
+            expect(traderInfo1.makerZrxBalance).to.be.bignumber.equal(makerZrxBalance);
+            expect(traderInfo1.makerZrxAllowance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo1.takerZrxBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo1.takerZrxAllowance).to.be.bignumber.equal(takerZrxAllowance);
+            expect(traderInfo2.makerBalance).to.be.bignumber.equal(makerBalance);
+            expect(traderInfo2.makerAllowance).to.be.bignumber.equal(makerAllowance);
+            expect(traderInfo2.takerBalance).to.be.bignumber.equal(ERC721_BALANCE);
+            expect(traderInfo2.takerAllowance).to.be.bignumber.equal(ERC721_ALLOWANCE);
+            expect(traderInfo2.makerZrxBalance).to.be.bignumber.equal(makerZrxBalance);
+            expect(traderInfo2.makerZrxAllowance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo2.takerZrxBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo2.takerZrxAllowance).to.be.bignumber.equal(takerZrxAllowance);
+        });
+    });
+    describe('getOrderAndTraderInfo', () => {
+        beforeEach(async () => {
+            signedOrder = await orderFactory.newSignedOrderAsync();
+        });
+        it('should return the correct info when no balances or allowances are set', async () => {
+            const [orderInfo, traderInfo] = await orderValidator.getOrderAndTraderInfo.callAsync(
+                signedOrder,
+                takerAddress,
+            );
+            const expectedOrderHash = orderHashUtils.getOrderHashHex(signedOrder);
+            expect(orderInfo.orderStatus).to.be.equal(OrderStatus.FILLABLE);
+            expect(orderInfo.orderHash).to.be.equal(expectedOrderHash);
+            expect(orderInfo.orderTakerAssetFilledAmount).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo.makerBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo.makerAllowance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo.takerBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo.takerAllowance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo.makerZrxBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo.makerZrxAllowance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo.takerZrxBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo.takerZrxAllowance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+        });
+        it('should return the correct info when balances and allowances are set', async () => {
+            const makerBalance = new BigNumber(123);
+            const makerAllowance = new BigNumber(456);
+            const makerZrxBalance = new BigNumber(789);
+            const takerZrxAllowance = new BigNumber(987);
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await erc20Token.setBalance.sendTransactionAsync(makerAddress, makerBalance),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await erc20Token.approve.sendTransactionAsync(erc20Proxy.address, makerAllowance, {
+                    from: makerAddress,
+                }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await zrxToken.setBalance.sendTransactionAsync(makerAddress, makerZrxBalance),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await zrxToken.approve.sendTransactionAsync(erc20Proxy.address, takerZrxAllowance, {
+                    from: takerAddress,
+                }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await erc721Token.mint.sendTransactionAsync(takerAddress, tokenId),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            const isApproved = true;
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await erc721Token.setApprovalForAll.sendTransactionAsync(erc721Proxy.address, isApproved, {
+                    from: takerAddress,
+                }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            const [orderInfo, traderInfo] = await orderValidator.getOrderAndTraderInfo.callAsync(
+                signedOrder,
+                takerAddress,
+            );
+            const expectedOrderHash = orderHashUtils.getOrderHashHex(signedOrder);
+            expect(orderInfo.orderStatus).to.be.equal(OrderStatus.FILLABLE);
+            expect(orderInfo.orderHash).to.be.equal(expectedOrderHash);
+            expect(orderInfo.orderTakerAssetFilledAmount).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo.makerBalance).to.be.bignumber.equal(makerBalance);
+            expect(traderInfo.makerAllowance).to.be.bignumber.equal(makerAllowance);
+            expect(traderInfo.takerBalance).to.be.bignumber.equal(ERC721_BALANCE);
+            expect(traderInfo.takerAllowance).to.be.bignumber.equal(ERC721_ALLOWANCE);
+            expect(traderInfo.makerZrxBalance).to.be.bignumber.equal(makerZrxBalance);
+            expect(traderInfo.makerZrxAllowance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo.takerZrxBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo.takerZrxAllowance).to.be.bignumber.equal(takerZrxAllowance);
+        });
+    });
+    describe('getOrdersAndTradersInfo', () => {
+        beforeEach(async () => {
+            signedOrder = await orderFactory.newSignedOrderAsync();
+            signedOrder2 = await orderFactory.newSignedOrderAsync({
+                takerAssetData: assetDataUtils.encodeERC721AssetData(erc721Token.address, tokenId2),
+            });
+        });
+        it('should return the correct info when no balances or allowances have been set', async () => {
+            const orders = [signedOrder, signedOrder2];
+            const takers = [takerAddress, takerAddress];
+            const [
+                [orderInfo1, orderInfo2],
+                [traderInfo1, traderInfo2],
+            ] = await orderValidator.getOrdersAndTradersInfo.callAsync(orders, takers);
+            const expectedOrderHash1 = orderHashUtils.getOrderHashHex(signedOrder);
+            const expectedOrderHash2 = orderHashUtils.getOrderHashHex(signedOrder2);
+            expect(orderInfo1.orderStatus).to.be.equal(OrderStatus.FILLABLE);
+            expect(orderInfo1.orderHash).to.be.equal(expectedOrderHash1);
+            expect(orderInfo1.orderTakerAssetFilledAmount).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(orderInfo2.orderStatus).to.be.equal(OrderStatus.FILLABLE);
+            expect(orderInfo2.orderHash).to.be.equal(expectedOrderHash2);
+            expect(orderInfo2.orderTakerAssetFilledAmount).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo1.makerBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo1.makerAllowance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo1.takerBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo1.takerAllowance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo1.makerZrxBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo1.makerZrxAllowance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo1.takerZrxBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo1.takerZrxAllowance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo2.makerBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo2.makerAllowance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo2.takerBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo2.takerAllowance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo2.makerZrxBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo2.makerZrxAllowance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo2.takerZrxBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo2.takerZrxAllowance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+        });
+        it('should return the correct info when balances and allowances are set', async () => {
+            const makerBalance = new BigNumber(123);
+            const makerAllowance = new BigNumber(456);
+            const makerZrxBalance = new BigNumber(789);
+            const takerZrxAllowance = new BigNumber(987);
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await erc20Token.setBalance.sendTransactionAsync(makerAddress, makerBalance),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await erc20Token.approve.sendTransactionAsync(erc20Proxy.address, makerAllowance, {
+                    from: makerAddress,
+                }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await zrxToken.setBalance.sendTransactionAsync(makerAddress, makerZrxBalance),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await zrxToken.approve.sendTransactionAsync(erc20Proxy.address, takerZrxAllowance, {
+                    from: takerAddress,
+                }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            const isApproved = true;
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await erc721Token.setApprovalForAll.sendTransactionAsync(erc721Proxy.address, isApproved, {
+                    from: takerAddress,
+                }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await erc721Token.mint.sendTransactionAsync(takerAddress, tokenId2),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            const orders = [signedOrder, signedOrder2];
+            const takers = [takerAddress, takerAddress];
+            const [
+                [orderInfo1, orderInfo2],
+                [traderInfo1, traderInfo2],
+            ] = await orderValidator.getOrdersAndTradersInfo.callAsync(orders, takers);
+            const expectedOrderHash1 = orderHashUtils.getOrderHashHex(signedOrder);
+            const expectedOrderHash2 = orderHashUtils.getOrderHashHex(signedOrder2);
+            expect(orderInfo1.orderStatus).to.be.equal(OrderStatus.FILLABLE);
+            expect(orderInfo1.orderHash).to.be.equal(expectedOrderHash1);
+            expect(orderInfo1.orderTakerAssetFilledAmount).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(orderInfo2.orderStatus).to.be.equal(OrderStatus.FILLABLE);
+            expect(orderInfo2.orderHash).to.be.equal(expectedOrderHash2);
+            expect(orderInfo2.orderTakerAssetFilledAmount).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo1.makerBalance).to.be.bignumber.equal(makerBalance);
+            expect(traderInfo1.makerAllowance).to.be.bignumber.equal(makerAllowance);
+            expect(traderInfo1.takerBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo1.takerAllowance).to.be.bignumber.equal(ERC721_ALLOWANCE);
+            expect(traderInfo1.makerZrxBalance).to.be.bignumber.equal(makerZrxBalance);
+            expect(traderInfo1.makerZrxAllowance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo1.takerZrxBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo1.takerZrxAllowance).to.be.bignumber.equal(takerZrxAllowance);
+            expect(traderInfo2.makerBalance).to.be.bignumber.equal(makerBalance);
+            expect(traderInfo2.makerAllowance).to.be.bignumber.equal(makerAllowance);
+            expect(traderInfo2.takerBalance).to.be.bignumber.equal(ERC721_BALANCE);
+            expect(traderInfo2.takerAllowance).to.be.bignumber.equal(ERC721_ALLOWANCE);
+            expect(traderInfo2.makerZrxBalance).to.be.bignumber.equal(makerZrxBalance);
+            expect(traderInfo2.makerZrxAllowance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo2.takerZrxBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(traderInfo2.takerZrxAllowance).to.be.bignumber.equal(takerZrxAllowance);
+        });
+    });
+});
+// tslint:disable:max-file-line-count
diff --git a/contracts/extensions/test/global_hooks.ts b/contracts/extensions/test/global_hooks.ts
new file mode 100644
index 000000000..f8ace376a
--- /dev/null
+++ b/contracts/extensions/test/global_hooks.ts
@@ -0,0 +1,17 @@
+import { env, EnvVars } from '@0x/dev-utils';
+
+import { coverage, profiler, provider } from '@0x/contracts-test-utils';
+before('start web3 provider', () => {
+    provider.start();
+});
+after('generate coverage report', async () => {
+    if (env.parseBoolean(EnvVars.SolidityCoverage)) {
+        const coverageSubprovider = coverage.getCoverageSubproviderSingleton();
+        await coverageSubprovider.writeCoverageAsync();
+    }
+    if (env.parseBoolean(EnvVars.SolidityProfiler)) {
+        const profilerSubprovider = profiler.getProfilerSubproviderSingleton();
+        await profilerSubprovider.writeProfilerOutputAsync();
+    }
+    provider.stop();
+});
diff --git a/contracts/extensions/test/utils/forwarder_wrapper.ts b/contracts/extensions/test/utils/forwarder_wrapper.ts
new file mode 100644
index 000000000..4c78ecd79
--- /dev/null
+++ b/contracts/extensions/test/utils/forwarder_wrapper.ts
@@ -0,0 +1,119 @@
+import { constants, formatters, LogDecoder, MarketSellOrders } 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, TxDataPayable } from 'ethereum-types';
+import * as _ from 'lodash';
+
+import { ForwarderContract } from '../../generated-wrappers/forwarder';
+import { artifacts } from '../../src/artifacts';
+
+export class ForwarderWrapper {
+    private readonly _web3Wrapper: Web3Wrapper;
+    private readonly _forwarderContract: ForwarderContract;
+    private readonly _logDecoder: LogDecoder;
+    public static getPercentageOfValue(value: BigNumber, percentage: number): BigNumber {
+        const numerator = constants.PERCENTAGE_DENOMINATOR.times(percentage).dividedToIntegerBy(100);
+        const newValue = value.times(numerator).dividedToIntegerBy(constants.PERCENTAGE_DENOMINATOR);
+        return newValue;
+    }
+    public static getWethForFeeOrders(feeAmount: BigNumber, feeOrders: SignedOrder[]): BigNumber {
+        let wethAmount = new BigNumber(0);
+        let remainingFeeAmount = feeAmount;
+        _.forEach(feeOrders, feeOrder => {
+            const feeAvailable = feeOrder.makerAssetAmount.minus(feeOrder.takerFee);
+            if (!remainingFeeAmount.isZero() && feeAvailable.gt(remainingFeeAmount)) {
+                wethAmount = wethAmount.plus(
+                    feeOrder.takerAssetAmount
+                        .times(remainingFeeAmount)
+                        .dividedBy(feeAvailable)
+                        .ceil(),
+                );
+                remainingFeeAmount = new BigNumber(0);
+            } else if (!remainingFeeAmount.isZero()) {
+                wethAmount = wethAmount.plus(feeOrder.takerAssetAmount);
+                remainingFeeAmount = remainingFeeAmount.minus(feeAvailable);
+            }
+        });
+        return wethAmount;
+    }
+    private static _createOptimizedOrders(signedOrders: SignedOrder[]): MarketSellOrders {
+        _.forEach(signedOrders, (signedOrder, index) => {
+            signedOrder.takerAssetData = constants.NULL_BYTES;
+            if (index > 0) {
+                signedOrder.makerAssetData = constants.NULL_BYTES;
+            }
+        });
+        const params = formatters.createMarketSellOrders(signedOrders, constants.ZERO_AMOUNT);
+        return params;
+    }
+    private static _createOptimizedZrxOrders(signedOrders: SignedOrder[]): MarketSellOrders {
+        _.forEach(signedOrders, signedOrder => {
+            signedOrder.makerAssetData = constants.NULL_BYTES;
+            signedOrder.takerAssetData = constants.NULL_BYTES;
+        });
+        const params = formatters.createMarketSellOrders(signedOrders, constants.ZERO_AMOUNT);
+        return params;
+    }
+    constructor(contractInstance: ForwarderContract, provider: Provider) {
+        this._forwarderContract = contractInstance;
+        this._web3Wrapper = new Web3Wrapper(provider);
+        this._logDecoder = new LogDecoder(this._web3Wrapper, { ...artifacts, ...tokensArtifacts });
+    }
+    public async marketSellOrdersWithEthAsync(
+        orders: SignedOrder[],
+        feeOrders: SignedOrder[],
+        txData: TxDataPayable,
+        opts: { feePercentage?: BigNumber; feeRecipient?: string } = {},
+    ): Promise<TransactionReceiptWithDecodedLogs> {
+        const params = ForwarderWrapper._createOptimizedOrders(orders);
+        const feeParams = ForwarderWrapper._createOptimizedZrxOrders(feeOrders);
+        const feePercentage = _.isUndefined(opts.feePercentage) ? constants.ZERO_AMOUNT : opts.feePercentage;
+        const feeRecipient = _.isUndefined(opts.feeRecipient) ? constants.NULL_ADDRESS : opts.feeRecipient;
+        const txHash = await this._forwarderContract.marketSellOrdersWithEth.sendTransactionAsync(
+            params.orders,
+            params.signatures,
+            feeParams.orders,
+            feeParams.signatures,
+            feePercentage,
+            feeRecipient,
+            txData,
+        );
+        const tx = await this._logDecoder.getTxWithDecodedLogsAsync(txHash);
+        return tx;
+    }
+    public async marketBuyOrdersWithEthAsync(
+        orders: SignedOrder[],
+        feeOrders: SignedOrder[],
+        makerAssetFillAmount: BigNumber,
+        txData: TxDataPayable,
+        opts: { feePercentage?: BigNumber; feeRecipient?: string } = {},
+    ): Promise<TransactionReceiptWithDecodedLogs> {
+        const params = ForwarderWrapper._createOptimizedOrders(orders);
+        const feeParams = ForwarderWrapper._createOptimizedZrxOrders(feeOrders);
+        const feePercentage = _.isUndefined(opts.feePercentage) ? constants.ZERO_AMOUNT : opts.feePercentage;
+        const feeRecipient = _.isUndefined(opts.feeRecipient) ? constants.NULL_ADDRESS : opts.feeRecipient;
+        const txHash = await this._forwarderContract.marketBuyOrdersWithEth.sendTransactionAsync(
+            params.orders,
+            makerAssetFillAmount,
+            params.signatures,
+            feeParams.orders,
+            feeParams.signatures,
+            feePercentage,
+            feeRecipient,
+            txData,
+        );
+        const tx = await this._logDecoder.getTxWithDecodedLogsAsync(txHash);
+        return tx;
+    }
+    public async withdrawAssetAsync(
+        assetData: string,
+        amount: BigNumber,
+        txData: TxDataPayable,
+    ): Promise<TransactionReceiptWithDecodedLogs> {
+        const txHash = await this._forwarderContract.withdrawAsset.sendTransactionAsync(assetData, amount, txData);
+        const tx = await this._logDecoder.getTxWithDecodedLogsAsync(txHash);
+        return tx;
+    }
+}
diff --git a/contracts/extensions/tsconfig.json b/contracts/extensions/tsconfig.json
new file mode 100644
index 000000000..c894eb367
--- /dev/null
+++ b/contracts/extensions/tsconfig.json
@@ -0,0 +1,15 @@
+{
+    "extends": "../../tsconfig",
+    "compilerOptions": {
+        "outDir": "lib",
+        "rootDir": ".",
+        "resolveJsonModule": true
+    },
+    "include": ["./src/**/*", "./test/**/*", "./generated-wrappers/**/*"],
+    "files": [
+        "./generated-artifacts/DutchAuction.json",
+        "./generated-artifacts/Forwarder.json",
+        "./generated-artifacts/OrderValidator.json"
+    ],
+    "exclude": ["./deploy/solc/solc_bin"]
+}
diff --git a/contracts/extensions/tslint.json b/contracts/extensions/tslint.json
new file mode 100644
index 000000000..1bb3ac2a2
--- /dev/null
+++ b/contracts/extensions/tslint.json
@@ -0,0 +1,6 @@
+{
+    "extends": ["@0x/tslint-config"],
+    "rules": {
+        "custom-no-magic-numbers": false
+    }
+}