Merge branch 'development' into feature/instant/processing-state

71 files changed, 1028 insertions, 180 deletions

diff --git a/CODEOWNERS b/CODEOWNERS
index 278234aff..ba40af31a 100644
--- a/CODEOWNERS
+++ b/CODEOWNERS
@@ -26,3 +26,4 @@ packages/subproviders/ @fabioberger @dekz
 packages/connect/ @fragosti 
 packages/monorepo-scripts/ @fabioberger
 packages/order-utils/ @fabioberger @LogvinovLeon 
+python-packages/ @feuGeneA
\ No newline at end of file
diff --git a/packages/asset-buyer/CHANGELOG.json b/packages/asset-buyer/CHANGELOG.json
index 5ebe2aa24..7ebcd8c2f 100644
--- a/packages/asset-buyer/CHANGELOG.json
+++ b/packages/asset-buyer/CHANGELOG.json
@@ -25,6 +25,10 @@
             {
                 "note": "Add missing types to public interface",
                 "pr": 1139
+            },
+            {
+                "note": "Throw `SignatureRequestDenied` and `TransactionValueTooLow` errors when executing buy",
+                "pr": 1147
             }
         ],
         "timestamp": 1539871071
diff --git a/packages/asset-buyer/src/asset_buyer.ts b/packages/asset-buyer/src/asset_buyer.ts
index 2fe8f6deb..2f9a3108e 100644
--- a/packages/asset-buyer/src/asset_buyer.ts
+++ b/packages/asset-buyer/src/asset_buyer.ts
@@ -1,4 +1,4 @@
-import { ContractWrappers } from '@0x/contract-wrappers';
+import { ContractWrappers, ContractWrappersError, ForwarderWrapperError } from '@0x/contract-wrappers';
 import { schemas } from '@0x/json-schemas';
 import { SignedOrder } from '@0x/order-utils';
 import { ObjectMap } from '@0x/types';
@@ -210,21 +210,32 @@ export class AssetBuyer {
                 throw new Error(AssetBuyerError.NoAddressAvailable);
             }
         }
-        // if no ethAmount is provided, default to the worst ethAmount from buyQuote
-        const txHash = await this._contractWrappers.forwarder.marketBuyOrdersWithEthAsync(
-            orders,
-            assetBuyAmount,
-            finalTakerAddress,
-            ethAmount || worstCaseQuoteInfo.totalEthAmount,
-            feeOrders,
-            feePercentage,
-            feeRecipient,
-            {
-                gasLimit,
-                gasPrice,
-            },
-        );
-        return txHash;
+        try {
+            // if no ethAmount is provided, default to the worst ethAmount from buyQuote
+            const txHash = await this._contractWrappers.forwarder.marketBuyOrdersWithEthAsync(
+                orders,
+                assetBuyAmount,
+                finalTakerAddress,
+                ethAmount || worstCaseQuoteInfo.totalEthAmount,
+                feeOrders,
+                feePercentage,
+                feeRecipient,
+                {
+                    gasLimit,
+                    gasPrice,
+                    shouldValidate: true,
+                },
+            );
+            return txHash;
+        } catch (err) {
+            if (_.includes(err.message, ContractWrappersError.SignatureRequestDenied)) {
+                throw new Error(AssetBuyerError.SignatureRequestDenied);
+            } else if (_.includes(err.message, ForwarderWrapperError.CompleteFillFailed)) {
+                throw new Error(AssetBuyerError.TransactionValueTooLow);
+            } else {
+                throw err;
+            }
+        }
     }
     /**
      * Grab orders from the map, if there is a miss or it is time to refresh, fetch and process the orders
diff --git a/packages/asset-buyer/src/types.ts b/packages/asset-buyer/src/types.ts
index 0d8e732d7..f15e7e934 100644
--- a/packages/asset-buyer/src/types.ts
+++ b/packages/asset-buyer/src/types.ts
@@ -112,6 +112,8 @@ export enum AssetBuyerError {
     NoAddressAvailable = 'NO_ADDRESS_AVAILABLE',
     InvalidOrderProviderResponse = 'INVALID_ORDER_PROVIDER_RESPONSE',
     AssetUnavailable = 'ASSET_UNAVAILABLE',
+    SignatureRequestDenied = 'SIGNATURE_REQUEST_DENIED',
+    TransactionValueTooLow = 'TRANSACTION_VALUE_TOO_LOW',
 }
 
 export interface OrdersAndFillableAmounts {
diff --git a/packages/contract-wrappers/CHANGELOG.json b/packages/contract-wrappers/CHANGELOG.json
index f66be3f0a..c3d986b4a 100644
--- a/packages/contract-wrappers/CHANGELOG.json
+++ b/packages/contract-wrappers/CHANGELOG.json
@@ -37,6 +37,14 @@
                 "note":
                     "Removed ContractNotFound errors. Checking for this error was somewhat ineffecient. Relevant methods/functions now return the default error from web3-wrapper, which we feel provides enough information.",
                 "pr": 1105
+            },
+            {
+                "note": "Add `ForwarderWrapperError` to public interface",
+                "pr": 1147
+            },
+            {
+                "note": "Add `ContractWrapperError.SignatureRequestDenied` to public interface",
+                "pr": 1147
             }
         ],
         "timestamp": 1539871071
diff --git a/packages/contract-wrappers/src/index.ts b/packages/contract-wrappers/src/index.ts
index a38bd122b..d66ff5c9c 100644
--- a/packages/contract-wrappers/src/index.ts
+++ b/packages/contract-wrappers/src/index.ts
@@ -39,6 +39,7 @@ export { TransactionEncoder } from './utils/transaction_encoder';
 
 export {
     ContractWrappersError,
+    ForwarderWrapperError,
     IndexedFilterValues,
     BlockRange,
     ContractWrappersConfig,
diff --git a/packages/contract-wrappers/src/types.ts b/packages/contract-wrappers/src/types.ts
index 60750179f..5a5bdd530 100644
--- a/packages/contract-wrappers/src/types.ts
+++ b/packages/contract-wrappers/src/types.ts
@@ -18,6 +18,10 @@ export enum ExchangeWrapperError {
     AssetDataMismatch = 'ASSET_DATA_MISMATCH',
 }
 
+export enum ForwarderWrapperError {
+    CompleteFillFailed = 'COMPLETE_FILL_FAILED',
+}
+
 export enum ContractWrappersError {
     ContractNotDeployedOnNetwork = 'CONTRACT_NOT_DEPLOYED_ON_NETWORK',
     InsufficientAllowanceForTransfer = 'INSUFFICIENT_ALLOWANCE_FOR_TRANSFER',
@@ -30,6 +34,7 @@ export enum ContractWrappersError {
     SubscriptionAlreadyPresent = 'SUBSCRIPTION_ALREADY_PRESENT',
     ERC721OwnerNotFound = 'ERC_721_OWNER_NOT_FOUND',
     ERC721NoApproval = 'ERC_721_NO_APPROVAL',
+    SignatureRequestDenied = 'SIGNATURE_REQUEST_DENIED',
 }
 
 export enum InternalContractWrappersError {
diff --git a/packages/contract-wrappers/src/utils/constants.ts b/packages/contract-wrappers/src/utils/constants.ts
index 9ff61f62a..c587ba526 100644
--- a/packages/contract-wrappers/src/utils/constants.ts
+++ b/packages/contract-wrappers/src/utils/constants.ts
@@ -14,4 +14,5 @@ export const constants = {
     ZERO_AMOUNT: new BigNumber(0),
     ONE_AMOUNT: new BigNumber(1),
     ETHER_TOKEN_DECIMALS: 18,
+    USER_DENIED_SIGNATURE_PATTERN: 'User denied transaction signature',
 };
diff --git a/packages/contract-wrappers/src/utils/decorators.ts b/packages/contract-wrappers/src/utils/decorators.ts
index e17246015..a4207ae4c 100644
--- a/packages/contract-wrappers/src/utils/decorators.ts
+++ b/packages/contract-wrappers/src/utils/decorators.ts
@@ -29,6 +29,14 @@ const schemaErrorTransformer = (error: Error) => {
     return error;
 };
 
+const signatureRequestErrorTransformer = (error: Error) => {
+    if (_.includes(error.message, constants.USER_DENIED_SIGNATURE_PATTERN)) {
+        const errMsg = ContractWrappersError.SignatureRequestDenied;
+        return new Error(errMsg);
+    }
+    return error;
+};
+
 /**
  * Source: https://stackoverflow.com/a/29837695/3546986
  */
@@ -87,7 +95,11 @@ const syncErrorHandlerFactory = (errorTransformer: ErrorTransformer) => {
 };
 
 // _.flow(f, g) = f ∘ g
-const zeroExErrorTransformer = _.flow(schemaErrorTransformer, contractCallErrorTransformer);
+const zeroExErrorTransformer = _.flow(
+    schemaErrorTransformer,
+    contractCallErrorTransformer,
+    signatureRequestErrorTransformer,
+);
 
 export const decorators = {
     asyncZeroExErrorHandler: asyncErrorHandlerFactory(zeroExErrorTransformer),
diff --git a/packages/contracts/contracts/extensions/Forwarder/MixinExchangeWrapper.sol b/packages/contracts/contracts/extensions/Forwarder/MixinExchangeWrapper.sol
index fea9a53c2..4991c0ea5 100644
--- a/packages/contracts/contracts/extensions/Forwarder/MixinExchangeWrapper.sol
+++ b/packages/contracts/contracts/extensions/Forwarder/MixinExchangeWrapper.sol
@@ -155,8 +155,10 @@ contract MixinExchangeWrapper is
             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
-            uint256 remainingTakerAssetFillAmount = getPartialAmountFloor(
+            // 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
@@ -224,7 +226,9 @@ contract MixinExchangeWrapper is
 
             // 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.
-            uint256 remainingWethSellAmount = getPartialAmountFloor(
+            // 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
@@ -233,7 +237,7 @@ contract MixinExchangeWrapper is
             // Attempt to sell the remaining amount of WETH.
             FillResults memory singleFillResult = fillOrderNoThrow(
                 orders[i],
-                safeAdd(remainingWethSellAmount, 1),  // we add 1 wei to the fill amount to make up for rounding errors
+                remainingWethSellAmount,
                 signatures[i]
             );
 
diff --git a/packages/contracts/test/extensions/forwarder.ts b/packages/contracts/test/extensions/forwarder.ts
index b76624fa9..c006be0fe 100644
--- a/packages/contracts/test/extensions/forwarder.ts
+++ b/packages/contracts/test/extensions/forwarder.ts
@@ -45,6 +45,7 @@ describe(ContractName.Forwarder, () => {
 
     let weth: DummyERC20TokenContract;
     let zrxToken: DummyERC20TokenContract;
+    let erc20TokenA: DummyERC20TokenContract;
     let erc721Token: DummyERC721TokenContract;
     let forwarderContract: ForwarderContract;
     let wethContract: WETH9Contract;
@@ -77,7 +78,6 @@ describe(ContractName.Forwarder, () => {
         erc20Wrapper = new ERC20Wrapper(provider, usedAddresses, owner);
 
         const numDummyErc20ToDeploy = 3;
-        let erc20TokenA;
         [erc20TokenA, zrxToken] = await erc20Wrapper.deployDummyTokensAsync(
             numDummyErc20ToDeploy,
             constants.DUMMY_TOKEN_DECIMALS,
@@ -902,6 +902,269 @@ describe(ContractName.Forwarder, () => {
             );
             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 () => {
diff --git a/packages/contracts/test/utils/forwarder_wrapper.ts b/packages/contracts/test/utils/forwarder_wrapper.ts
index f1a64d47d..a0bfcfe1d 100644
--- a/packages/contracts/test/utils/forwarder_wrapper.ts
+++ b/packages/contracts/test/utils/forwarder_wrapper.ts
@@ -26,9 +26,12 @@ export class ForwarderWrapper {
         _.forEach(feeOrders, feeOrder => {
             const feeAvailable = feeOrder.makerAssetAmount.minus(feeOrder.takerFee);
             if (!remainingFeeAmount.isZero() && feeAvailable.gt(remainingFeeAmount)) {
-                wethAmount = wethAmount
-                    .plus(feeOrder.takerAssetAmount.times(remainingFeeAmount).dividedToIntegerBy(feeAvailable))
-                    .plus(1);
+                wethAmount = wethAmount.plus(
+                    feeOrder.takerAssetAmount
+                        .times(remainingFeeAmount)
+                        .dividedBy(feeAvailable)
+                        .ceil(),
+                );
                 remainingFeeAmount = new BigNumber(0);
             } else if (!remainingFeeAmount.isZero()) {
                 wethAmount = wethAmount.plus(feeOrder.takerAssetAmount);
diff --git a/packages/instant/src/components/buy_button.tsx b/packages/instant/src/components/buy_button.tsx
index 1afd216d8..9c42f3d87 100644
--- a/packages/instant/src/components/buy_button.tsx
+++ b/packages/instant/src/components/buy_button.tsx
@@ -23,7 +23,7 @@ export class BuyButton extends React.Component<BuyButtonProps> {
         onBuyFailure: util.boundNoop,
     };
     public render(): React.ReactNode {
-        const shouldDisableButton = _.isUndefined(this.props.buyQuote);
+        const shouldDisableButton = _.isUndefined(this.props.buyQuote) || _.isUndefined(this.props.assetBuyer);
         return (
             <Button width="100%" onClick={this._handleClick} isDisabled={shouldDisableButton}>
                 <Text fontColor={ColorOption.white} fontWeight={600} fontSize="20px">
diff --git a/packages/instant/src/components/buy_order_state_button.tsx b/packages/instant/src/components/buy_order_state_button.tsx
new file mode 100644
index 000000000..5bc965c7d
--- /dev/null
+++ b/packages/instant/src/components/buy_order_state_button.tsx
@@ -0,0 +1,23 @@
+import * as React from 'react';
+
+import { PlacingOrderButton } from '../components/placing_order_button';
+import { SelectedAssetBuyButton } from '../containers/selected_asset_buy_button';
+import { SelectedAssetRetryButton } from '../containers/selected_asset_retry_button';
+import { SelectedAssetViewTransactionButton } from '../containers/selected_asset_view_transaction_button';
+import { AsyncProcessState } from '../types';
+
+export interface BuyOrderStateButtonProps {
+    buyOrderProcessingState: AsyncProcessState;
+}
+
+export const BuyOrderStateButton: React.StatelessComponent<BuyOrderStateButtonProps> = props => {
+    if (props.buyOrderProcessingState === AsyncProcessState.FAILURE) {
+        return <SelectedAssetRetryButton />;
+    } else if (props.buyOrderProcessingState === AsyncProcessState.SUCCESS) {
+        return <SelectedAssetViewTransactionButton />;
+    } else if (props.buyOrderProcessingState === AsyncProcessState.PENDING) {
+        return <PlacingOrderButton />;
+    }
+
+    return <SelectedAssetBuyButton />;
+};
diff --git a/packages/instant/src/components/zero_ex_instant.tsx b/packages/instant/src/components/zero_ex_instant.tsx
index 142e74dae..ffa5a8250 100644
--- a/packages/instant/src/components/zero_ex_instant.tsx
+++ b/packages/instant/src/components/zero_ex_instant.tsx
@@ -31,7 +31,7 @@ export interface ZeroExInstantOptionalProps {
 }
 
 export class ZeroExInstant extends React.Component<ZeroExInstantProps> {
-    public store: Store;
+    private readonly _store: Store;
     private static _mergeInitialStateWithProps(props: ZeroExInstantProps, state: State = INITIAL_STATE): State {
         // Create merged object such that properties in props override default settings
         const optionalPropsWithDefaults: ZeroExInstantOptionalProps = {
@@ -58,14 +58,14 @@ export class ZeroExInstant extends React.Component<ZeroExInstantProps> {
     }
     constructor(props: ZeroExInstantProps) {
         super(props);
-        this.store = store.create(ZeroExInstant._mergeInitialStateWithProps(this.props, INITIAL_STATE));
+        this._store = store.create(ZeroExInstant._mergeInitialStateWithProps(this.props, INITIAL_STATE));
         // tslint:disable-next-line:no-floating-promises
-        asyncData.fetchAndDispatchToStore(this.store);
+        asyncData.fetchAndDispatchToStore(this._store);
     }
 
     public render(): React.ReactNode {
         return (
-            <Provider store={this.store}>
+            <Provider store={this._store}>
                 <SelectedAssetThemeProvider>
                     <ZeroExInstantContainer />
                 </SelectedAssetThemeProvider>
diff --git a/packages/instant/src/components/zero_ex_instant_container.tsx b/packages/instant/src/components/zero_ex_instant_container.tsx
index 088d0a93e..1d17ed12a 100644
--- a/packages/instant/src/components/zero_ex_instant_container.tsx
+++ b/packages/instant/src/components/zero_ex_instant_container.tsx
@@ -2,7 +2,7 @@ import * as React from 'react';
 
 import { LatestBuyQuoteOrderDetails } from '../containers/latest_buy_quote_order_details';
 import { LatestError } from '../containers/latest_error';
-import { SelectedAssetButton } from '../containers/selected_asset_button';
+import { SelectedAssetBuyOrderStateButton } from '../containers/selected_asset_buy_order_state_button';
 import { SelectedAssetInstantHeading } from '../containers/selected_asset_instant_heading';
 
 import { ColorOption } from '../style/theme';
@@ -27,7 +27,7 @@ export const ZeroExInstantContainer: React.StatelessComponent<ZeroExInstantConta
                 <SelectedAssetInstantHeading />
                 <LatestBuyQuoteOrderDetails />
                 <Container padding="20px" width="100%">
-                    <SelectedAssetButton />
+                    <SelectedAssetBuyOrderStateButton />
                 </Container>
             </Flex>
         </Container>
diff --git a/packages/instant/src/constants.ts b/packages/instant/src/constants.ts
index 7f4c5a058..31491c80a 100644
--- a/packages/instant/src/constants.ts
+++ b/packages/instant/src/constants.ts
@@ -1,3 +1,4 @@
 import { BigNumber } from '@0x/utils';
 export const BIG_NUMBER_ZERO = new BigNumber(0);
 export const ethDecimals = 18;
+export const DEFAULT_ZERO_EX_CONTAINER_SELECTOR = '#zeroExInstantContainer';
diff --git a/packages/instant/src/containers/selected_asset_button.tsx b/packages/instant/src/containers/selected_asset_button.tsx
deleted file mode 100644
index d368d05e1..000000000
--- a/packages/instant/src/containers/selected_asset_button.tsx
+++ /dev/null
@@ -1,39 +0,0 @@
-import * as _ from 'lodash';
-import * as React from 'react';
-import { connect } from 'react-redux';
-
-import { SecondaryButton } from '../components/secondary_button';
-import { State } from '../redux/reducer';
-import { AsyncProcessState, OrderState } from '../types';
-
-import { PlacingOrderButton } from '../components/placing_order_button';
-
-import { SelectedAssetBuyButton } from './selected_asset_buy_button';
-import { SelectedAssetRetryButton } from './selected_asset_retry_button';
-import { SelectedAssetViewTransactionButton } from './selected_asset_view_transaction_button';
-
-interface ConnectedState {
-    buyOrderState: OrderState;
-}
-export interface SelectedAssetButtonProps {}
-const mapStateToProps = (state: State, _ownProps: SelectedAssetButtonProps): ConnectedState => ({
-    buyOrderState: state.buyOrderState,
-});
-
-const SelectedAssetButtonPresentationComponent: React.StatelessComponent<{
-    buyOrderState: OrderState;
-}> = props => {
-    if (props.buyOrderState.processState === AsyncProcessState.FAILURE) {
-        return <SelectedAssetRetryButton />;
-    } else if (props.buyOrderState.processState === AsyncProcessState.SUCCESS) {
-        return <SelectedAssetViewTransactionButton />;
-    } else if (props.buyOrderState.processState === AsyncProcessState.PENDING) {
-        return <PlacingOrderButton />;
-    }
-
-    return <SelectedAssetBuyButton />;
-};
-
-export const SelectedAssetButton: React.ComponentClass<SelectedAssetButtonProps> = connect(mapStateToProps)(
-    SelectedAssetButtonPresentationComponent,
-);
diff --git a/packages/instant/src/containers/selected_asset_buy_order_state_button.tsx b/packages/instant/src/containers/selected_asset_buy_order_state_button.tsx
new file mode 100644
index 000000000..f3efbb5d2
--- /dev/null
+++ b/packages/instant/src/containers/selected_asset_buy_order_state_button.tsx
@@ -0,0 +1,20 @@
+import * as _ from 'lodash';
+import * as React from 'react';
+import { connect } from 'react-redux';
+
+import { State } from '../redux/reducer';
+import { AsyncProcessState } from '../types';
+
+import { BuyOrderStateButton } from '../components/buy_order_state_button';
+
+interface ConnectedState {
+    buyOrderProcessingState: AsyncProcessState;
+}
+export interface SelectedAssetButtonProps {}
+const mapStateToProps = (state: State, _ownProps: SelectedAssetButtonProps): ConnectedState => ({
+    buyOrderProcessingState: state.buyOrderState.processState,
+});
+
+export const SelectedAssetBuyOrderStateButton: React.ComponentClass<SelectedAssetButtonProps> = connect(
+    mapStateToProps,
+)(BuyOrderStateButton);
diff --git a/packages/instant/src/containers/selected_asset_retry_button.tsx b/packages/instant/src/containers/selected_asset_retry_button.tsx
index 66177551d..b2b140be6 100644
--- a/packages/instant/src/containers/selected_asset_retry_button.tsx
+++ b/packages/instant/src/containers/selected_asset_retry_button.tsx
@@ -17,10 +17,10 @@ const mapDispatchToProps = (
     dispatch: Dispatch<Action>,
     _ownProps: SelectedAssetRetryButtonProps,
 ): ConnectedDispatch => ({
-    onClick: () => dispatch(actions.clearBuyQuoteAndSelectedAssetAmount()),
+    onClick: () => dispatch(actions.resetAmount()),
 });
 
 export const SelectedAssetRetryButton: React.ComponentClass<SelectedAssetRetryButtonProps> = connect(
-    null,
+    undefined,
     mapDispatchToProps,
 )(RetryButton);
diff --git a/packages/instant/src/index.umd.ts b/packages/instant/src/index.umd.ts
index fe78ce401..f648b37f2 100644
--- a/packages/instant/src/index.umd.ts
+++ b/packages/instant/src/index.umd.ts
@@ -1,8 +1,9 @@
 import * as React from 'react';
 import * as ReactDOM from 'react-dom';
 
+import { DEFAULT_ZERO_EX_CONTAINER_SELECTOR } from './constants';
 import { ZeroExInstant, ZeroExInstantProps } from './index';
 
-export const render = (props: ZeroExInstantProps, selector: string = '#zeroExInstantContainer') => {
+export const render = (props: ZeroExInstantProps, selector: string = DEFAULT_ZERO_EX_CONTAINER_SELECTOR) => {
     ReactDOM.render(React.createElement(ZeroExInstant, props), document.querySelector(selector));
 };
diff --git a/packages/instant/src/redux/actions.ts b/packages/instant/src/redux/actions.ts
index 1360634d7..9c084ab3c 100644
--- a/packages/instant/src/redux/actions.ts
+++ b/packages/instant/src/redux/actions.ts
@@ -31,7 +31,7 @@ export enum ActionTypes {
     SET_ERROR = 'SET_ERROR',
     HIDE_ERROR = 'HIDE_ERROR',
     CLEAR_ERROR = 'CLEAR_ERROR',
-    CLEAR_BUY_QUOTE_AND_SELECTED_ASSET_AMOUNT = 'CLEAR_BUY_QUOTE_AND_SELECTED_ASSET_AMOUNT',
+    RESET_AMOUNT = 'RESET_AMOUNT',
 }
 
 export const actions = {
@@ -45,5 +45,5 @@ export const actions = {
     setError: (error?: any) => createAction(ActionTypes.SET_ERROR, error),
     hideError: () => createAction(ActionTypes.HIDE_ERROR),
     clearError: () => createAction(ActionTypes.CLEAR_ERROR),
-    clearBuyQuoteAndSelectedAssetAmount: () => createAction(ActionTypes.CLEAR_BUY_QUOTE_AND_SELECTED_ASSET_AMOUNT),
+    resetAmount: () => createAction(ActionTypes.RESET_AMOUNT),
 };
diff --git a/packages/instant/src/redux/reducer.ts b/packages/instant/src/redux/reducer.ts
index 1aedcbcc4..c6a05ac52 100644
--- a/packages/instant/src/redux/reducer.ts
+++ b/packages/instant/src/redux/reducer.ts
@@ -101,7 +101,7 @@ export const reducer = (state: State = INITIAL_STATE, action: Action): State =>
                 ...state,
                 selectedAsset: newSelectedAsset,
             };
-        case ActionTypes.CLEAR_BUY_QUOTE_AND_SELECTED_ASSET_AMOUNT:
+        case ActionTypes.RESET_AMOUNT:
             return {
                 ...state,
                 latestBuyQuote: undefined,
diff --git a/packages/instant/src/types.ts b/packages/instant/src/types.ts
index b7b16f4d7..c5521c63c 100644
--- a/packages/instant/src/types.ts
+++ b/packages/instant/src/types.ts
@@ -55,6 +55,7 @@ export interface ERC721Asset {
     assetData: string;
     metaData: ERC721AssetMetaData;
 }
+
 export interface Asset {
     assetData: string;
     metaData: AssetMetaData;
diff --git a/packages/instant/test/util/asset.test.ts b/packages/instant/test/util/asset.test.ts
new file mode 100644
index 000000000..c7db7eba7
--- /dev/null
+++ b/packages/instant/test/util/asset.test.ts
@@ -0,0 +1,47 @@
+import { AssetProxyId, ObjectMap } from '@0x/types';
+
+import { Asset, AssetMetaData, ERC20AssetMetaData, Network, ZeroExInstantError } from '../../src/types';
+import { assetUtils } from '../../src/util/asset';
+
+const ZRX_ASSET_DATA = '0xf47261b0000000000000000000000000e41d2489571d322189246dafa5ebde1f4699f498';
+const ZRX_ASSET_DATA_KOVAN = '0xf47261b00000000000000000000000002002d3812f58e35f0ea1ffbf80a75a38c32175fa';
+const ZRX_META_DATA: ERC20AssetMetaData = {
+    assetProxyId: AssetProxyId.ERC20,
+    symbol: 'zrx',
+    decimals: 18,
+};
+const ZRX_ASSET: Asset = {
+    assetData: ZRX_ASSET_DATA,
+    metaData: ZRX_META_DATA,
+};
+const META_DATA_MAP: ObjectMap<AssetMetaData> = {
+    [ZRX_ASSET_DATA]: ZRX_META_DATA,
+};
+
+describe('assetDataUtil', () => {
+    describe('bestNameForAsset', () => {
+        it('should return default string if assetData is undefined', () => {
+            expect(assetUtils.bestNameForAsset(undefined, 'xyz')).toEqual('xyz');
+        });
+        it('should return ZRX for ZRX assetData', () => {
+            expect(assetUtils.bestNameForAsset(ZRX_ASSET, 'mah default')).toEqual('ZRX');
+        });
+    });
+    describe('getMetaDataOrThrow', () => {
+        it('should return the metaData for the supplied mainnet asset data', () => {
+            expect(assetUtils.getMetaDataOrThrow(ZRX_ASSET_DATA, META_DATA_MAP, Network.Mainnet)).toEqual(
+                ZRX_META_DATA,
+            );
+        });
+        it('should return the metaData for the supplied non-mainnet asset data', () => {
+            expect(assetUtils.getMetaDataOrThrow(ZRX_ASSET_DATA_KOVAN, META_DATA_MAP, Network.Kovan)).toEqual(
+                ZRX_META_DATA,
+            );
+        });
+        it('should throw if the metaData for the asset is not available', () => {
+            expect(() =>
+                assetUtils.getMetaDataOrThrow('asset data we dont have', META_DATA_MAP, Network.Mainnet),
+            ).toThrowError(ZeroExInstantError.AssetMetaDataNotAvailable);
+        });
+    });
+});
diff --git a/packages/json-schemas/CHANGELOG.json b/packages/json-schemas/CHANGELOG.json
index 8a88df6e2..3bd6552e3 100644
--- a/packages/json-schemas/CHANGELOG.json
+++ b/packages/json-schemas/CHANGELOG.json
@@ -1,5 +1,15 @@
 [
     {
+        "version": "2.0.1",
+        "changes": [
+            {
+                "note":
+                    "Improve schemas by enforcing that amounts that must be whole numbers (e.g Order asset amounts) no longer allow decimal amounts",
+                "pr": 1173
+            }
+        ]
+    },
+    {
         "version": "2.0.0",
         "changes": [
             {
diff --git a/packages/json-schemas/schemas/order_cancel_schema.json b/packages/json-schemas/schemas/order_cancel_schema.json
index 09d4068c6..8d0999941 100644
--- a/packages/json-schemas/schemas/order_cancel_schema.json
+++ b/packages/json-schemas/schemas/order_cancel_schema.json
@@ -4,7 +4,7 @@
     "items": {
         "properties": {
             "order": { "$ref": "/orderSchema" },
-            "takerTokenCancelAmount": { "$ref": "/numberSchema" }
+            "takerTokenCancelAmount": { "$ref": "/wholeNumberSchema" }
         },
         "required": ["order", "takerTokenCancelAmount"],
         "type": "object"
diff --git a/packages/json-schemas/schemas/order_fill_or_kill_requests_schema.json b/packages/json-schemas/schemas/order_fill_or_kill_requests_schema.json
index c9549c72e..73bbf20bb 100644
--- a/packages/json-schemas/schemas/order_fill_or_kill_requests_schema.json
+++ b/packages/json-schemas/schemas/order_fill_or_kill_requests_schema.json
@@ -4,7 +4,7 @@
     "items": {
         "properties": {
             "signedOrder": { "$ref": "/signedOrderSchema" },
-            "fillTakerAmount": { "$ref": "/numberSchema" }
+            "fillTakerAmount": { "$ref": "/wholeNumberSchema" }
         },
         "required": ["signedOrder", "fillTakerAmount"],
         "type": "object"
diff --git a/packages/json-schemas/schemas/order_fill_requests_schema.json b/packages/json-schemas/schemas/order_fill_requests_schema.json
index 98325653b..d06fb19a2 100644
--- a/packages/json-schemas/schemas/order_fill_requests_schema.json
+++ b/packages/json-schemas/schemas/order_fill_requests_schema.json
@@ -4,7 +4,7 @@
     "items": {
         "properties": {
             "signedOrder": { "$ref": "/signedOrderSchema" },
-            "takerTokenFillAmount": { "$ref": "/numberSchema" }
+            "takerTokenFillAmount": { "$ref": "/wholeNumberSchema" }
         },
         "required": ["signedOrder", "takerTokenFillAmount"],
         "type": "object"
diff --git a/packages/json-schemas/schemas/order_schema.json b/packages/json-schemas/schemas/order_schema.json
index de2c8c7c2..c70b9e2dd 100644
--- a/packages/json-schemas/schemas/order_schema.json
+++ b/packages/json-schemas/schemas/order_schema.json
@@ -3,17 +3,17 @@
     "properties": {
         "makerAddress": { "$ref": "/addressSchema" },
         "takerAddress": { "$ref": "/addressSchema" },
-        "makerFee": { "$ref": "/numberSchema" },
-        "takerFee": { "$ref": "/numberSchema" },
+        "makerFee": { "$ref": "/wholeNumberSchema" },
+        "takerFee": { "$ref": "/wholeNumberSchema" },
         "senderAddress": { "$ref": "/addressSchema" },
-        "makerAssetAmount": { "$ref": "/numberSchema" },
-        "takerAssetAmount": { "$ref": "/numberSchema" },
+        "makerAssetAmount": { "$ref": "/wholeNumberSchema" },
+        "takerAssetAmount": { "$ref": "/wholeNumberSchema" },
         "makerAssetData": { "$ref": "/hexSchema" },
         "takerAssetData": { "$ref": "/hexSchema" },
-        "salt": { "$ref": "/numberSchema" },
+        "salt": { "$ref": "/wholeNumberSchema" },
         "exchangeAddress": { "$ref": "/addressSchema" },
         "feeRecipientAddress": { "$ref": "/addressSchema" },
-        "expirationTimeSeconds": { "$ref": "/numberSchema" }
+        "expirationTimeSeconds": { "$ref": "/wholeNumberSchema" }
     },
     "required": [
         "makerAddress",
diff --git a/packages/json-schemas/schemas/relayer_api_asset_data_trade_info_schema.json b/packages/json-schemas/schemas/relayer_api_asset_data_trade_info_schema.json
index 0ab9b444f..e0f274c5d 100644
--- a/packages/json-schemas/schemas/relayer_api_asset_data_trade_info_schema.json
+++ b/packages/json-schemas/schemas/relayer_api_asset_data_trade_info_schema.json
@@ -3,8 +3,8 @@
     "type": "object",
     "properties": {
         "assetData": { "$ref": "/hexSchema" },
-        "minAmount": { "$ref": "/numberSchema" },
-        "maxAmount": { "$ref": "/numberSchema" },
+        "minAmount": { "$ref": "/wholeNumberSchema" },
+        "maxAmount": { "$ref": "/wholeNumberSchema" },
         "precision": { "type": "number" }
     },
     "required": ["assetData"]
diff --git a/packages/json-schemas/schemas/relayer_api_order_config_payload_schema.json b/packages/json-schemas/schemas/relayer_api_order_config_payload_schema.json
index bc95b61ef..f4583fc62 100644
--- a/packages/json-schemas/schemas/relayer_api_order_config_payload_schema.json
+++ b/packages/json-schemas/schemas/relayer_api_order_config_payload_schema.json
@@ -4,12 +4,12 @@
     "properties": {
         "makerAddress": { "$ref": "/addressSchema" },
         "takerAddress": { "$ref": "/addressSchema" },
-        "makerAssetAmount": { "$ref": "/numberSchema" },
-        "takerAssetAmount": { "$ref": "/numberSchema" },
+        "makerAssetAmount": { "$ref": "/wholeNumberSchema" },
+        "takerAssetAmount": { "$ref": "/wholeNumberSchema" },
         "makerAssetData": { "$ref": "/hexSchema" },
         "takerAssetData": { "$ref": "/hexSchema" },
         "exchangeAddress": { "$ref": "/addressSchema" },
-        "expirationTimeSeconds": { "$ref": "/numberSchema" }
+        "expirationTimeSeconds": { "$ref": "/wholeNumberSchema" }
     },
     "required": [
         "makerAddress",
diff --git a/packages/json-schemas/schemas/relayer_api_order_config_response_schema.json b/packages/json-schemas/schemas/relayer_api_order_config_response_schema.json
index 0742febdf..8193861e1 100644
--- a/packages/json-schemas/schemas/relayer_api_order_config_response_schema.json
+++ b/packages/json-schemas/schemas/relayer_api_order_config_response_schema.json
@@ -2,8 +2,8 @@
     "id": "/relayerApiOrderConfigResponseSchema",
     "type": "object",
     "properties": {
-        "makerFee": { "$ref": "/numberSchema" },
-        "takerFee": { "$ref": "/numberSchema" },
+        "makerFee": { "$ref": "/wholeNumberSchema" },
+        "takerFee": { "$ref": "/wholeNumberSchema" },
         "feeRecipientAddress": { "$ref": "/addressSchema" },
         "senderAddress": { "$ref": "/addressSchema" }
     },
diff --git a/packages/json-schemas/schemas/whole_number_schema.json b/packages/json-schemas/schemas/whole_number_schema.json
new file mode 100644
index 000000000..944ce820e
--- /dev/null
+++ b/packages/json-schemas/schemas/whole_number_schema.json
@@ -0,0 +1,5 @@
+{
+    "id": "/wholeNumberSchema",
+    "type": "string",
+    "pattern": "^\\d+$"
+}
diff --git a/packages/json-schemas/schemas/zero_ex_transaction_schema.json b/packages/json-schemas/schemas/zero_ex_transaction_schema.json
index ad3b11583..0c714f14d 100644
--- a/packages/json-schemas/schemas/zero_ex_transaction_schema.json
+++ b/packages/json-schemas/schemas/zero_ex_transaction_schema.json
@@ -3,7 +3,7 @@
     "properties": {
         "data": { "$ref": "/hexSchema" },
         "signerAddress": { "$ref": "/addressSchema" },
-        "salt": { "$ref": "/numberSchema" }
+        "salt": { "$ref": "/wholeNumberSchema" }
     },
     "required": ["data", "salt", "signerAddress"],
     "type": "object"
diff --git a/packages/json-schemas/src/schemas.ts b/packages/json-schemas/src/schemas.ts
index 8318df617..8ece5de75 100644
--- a/packages/json-schemas/src/schemas.ts
+++ b/packages/json-schemas/src/schemas.ts
@@ -34,6 +34,7 @@ import * as signedOrderSchema from '../schemas/signed_order_schema.json';
 import * as signedOrdersSchema from '../schemas/signed_orders_schema.json';
 import * as tokenSchema from '../schemas/token_schema.json';
 import * as txDataSchema from '../schemas/tx_data_schema.json';
+import * as wholeNumberSchema from '../schemas/whole_number_schema.json';
 import * as zeroExTransactionSchema from '../schemas/zero_ex_transaction_schema.json';
 
 export const schemas = {
@@ -74,4 +75,5 @@ export const schemas = {
     relayerApiOrdersResponseSchema,
     relayerApiAssetDataPairsSchema,
     zeroExTransactionSchema,
+    wholeNumberSchema,
 };
diff --git a/packages/json-schemas/test/schema_test.ts b/packages/json-schemas/test/schema_test.ts
index 795261ef2..bfa2c5668 100644
--- a/packages/json-schemas/test/schema_test.ts
+++ b/packages/json-schemas/test/schema_test.ts
@@ -36,6 +36,7 @@ const {
     relayerApiOrdersChannelUpdateSchema,
     relayerApiOrdersResponseSchema,
     relayerApiOrderSchema,
+    wholeNumberSchema,
 } = schemas;
 
 describe('Schema', () => {
@@ -73,6 +74,17 @@ describe('Schema', () => {
             validateAgainstSchema(testCases, numberSchema, shouldFail);
         });
     });
+    describe('#wholeNumberSchema', () => {
+        it('should validate valid numbers', () => {
+            const testCases = ['5', '42', '0'];
+            validateAgainstSchema(testCases, wholeNumberSchema);
+        });
+        it('should fail for invalid numbers', () => {
+            const testCases = ['1.3', '0.2', '00.00', '.3', '1.', 'abacaba', 'и', '1..0'];
+            const shouldFail = true;
+            validateAgainstSchema(testCases, wholeNumberSchema, shouldFail);
+        });
+    });
     describe('#addressSchema', () => {
         it('should validate valid addresses', () => {
             const testCases = ['0x8b0292b11a196601ed2ce54b665cafeca0347d42', NULL_ADDRESS];
diff --git a/packages/json-schemas/tsconfig.json b/packages/json-schemas/tsconfig.json
index 425dfcfe1..7b14166c0 100644
--- a/packages/json-schemas/tsconfig.json
+++ b/packages/json-schemas/tsconfig.json
@@ -43,6 +43,7 @@
         "./schemas/js_number.json",
         "./schemas/zero_ex_transaction_schema.json",
         "./schemas/tx_data_schema.json",
-        "./schemas/index_filter_values_schema.json"
+        "./schemas/index_filter_values_schema.json",
+        "./schemas/whole_number_schema.json"
     ]
 }
diff --git a/packages/monorepo-scripts/CHANGELOG.json b/packages/monorepo-scripts/CHANGELOG.json
index 4797fd929..170a97a33 100644
--- a/packages/monorepo-scripts/CHANGELOG.json
+++ b/packages/monorepo-scripts/CHANGELOG.json
@@ -9,6 +9,10 @@
             {
                 "note": "Add AssetBuyerError to the IGNORED_EXCESSIVE_TYPES array",
                 "pr": 1139
+            },
+            {
+                "note": "Add ForwarderError to the IGNORED_EXCESSIVE_TYPES array",
+                "pr": 1147
             }
         ]
     },
diff --git a/packages/monorepo-scripts/src/doc_gen_configs.ts b/packages/monorepo-scripts/src/doc_gen_configs.ts
index 0aaf5a6a5..7a14f8664 100644
--- a/packages/monorepo-scripts/src/doc_gen_configs.ts
+++ b/packages/monorepo-scripts/src/doc_gen_configs.ts
@@ -56,6 +56,7 @@ export const docGenConfigs: DocGenConfigs = {
         'ContractWrappersError',
         'OrderError',
         'AssetBuyerError',
+        'ForwarderWrapperError',
     ],
     // Some libraries only export types. In those cases, we cannot check if the exported types are part of the
     // "exported public interface". Thus we add them here and skip those checks.
diff --git a/packages/order-utils/test/asset_data_utils_test.ts b/packages/order-utils/test/asset_data_utils_test.ts
new file mode 100644
index 000000000..f8b850604
--- /dev/null
+++ b/packages/order-utils/test/asset_data_utils_test.ts
@@ -0,0 +1,31 @@
+import * as chai from 'chai';
+
+import { ERC20AssetData } from '@0x/types';
+
+import { assetDataUtils } from '../src/asset_data_utils';
+
+import { chaiSetup } from './utils/chai_setup';
+
+chaiSetup.configure();
+const expect = chai.expect;
+
+const KNOWN_ENCODINGS = [
+    {
+        address: '0x1dc4c1cefef38a777b15aa20260a54e584b16c48',
+        assetData: '0xf47261b00000000000000000000000001dc4c1cefef38a777b15aa20260a54e584b16c48',
+    },
+];
+
+const ERC20_ASSET_PROXY_ID = '0xf47261b0';
+
+describe('assetDataUtils', () => {
+    it('should encode', () => {
+        const assetData = assetDataUtils.encodeERC20AssetData(KNOWN_ENCODINGS[0].address);
+        expect(assetData).to.equal(KNOWN_ENCODINGS[0].assetData);
+    });
+    it('should decode', () => {
+        const assetData: ERC20AssetData = assetDataUtils.decodeERC20AssetData(KNOWN_ENCODINGS[0].assetData);
+        expect(assetData.tokenAddress).to.equal(KNOWN_ENCODINGS[0].address);
+        expect(assetData.assetProxyId).to.equal(ERC20_ASSET_PROXY_ID);
+    });
+});
diff --git a/packages/web3-wrapper/CHANGELOG.json b/packages/web3-wrapper/CHANGELOG.json
index b8d06eac1..6b554110f 100644
--- a/packages/web3-wrapper/CHANGELOG.json
+++ b/packages/web3-wrapper/CHANGELOG.json
@@ -1,5 +1,15 @@
 [
     {
+        "version": "3.1.1",
+        "changes": [
+            {
+                "note":
+                    "Fix bug in `getTransactionByHashAsync` which was causing the return value to have the wrong type (raw fields instead of unmarshalled fields).",
+                "pr": 1177
+            }
+        ]
+    },
+    {
         "version": "3.1.0",
         "changes": [
             {
diff --git a/packages/web3-wrapper/src/web3_wrapper.ts b/packages/web3-wrapper/src/web3_wrapper.ts
index 3ba153680..56877fef3 100644
--- a/packages/web3-wrapper/src/web3_wrapper.ts
+++ b/packages/web3-wrapper/src/web3_wrapper.ts
@@ -23,7 +23,13 @@ import {
 import * as _ from 'lodash';
 
 import { marshaller } from './marshaller';
-import { BlockWithoutTransactionDataRPC, BlockWithTransactionDataRPC, NodeType, Web3WrapperErrors } from './types';
+import {
+    BlockWithoutTransactionDataRPC,
+    BlockWithTransactionDataRPC,
+    NodeType,
+    TransactionRPC,
+    Web3WrapperErrors,
+} from './types';
 import { utils } from './utils';
 
 const BASE_TEN = 10;
@@ -228,10 +234,11 @@ export class Web3Wrapper {
      */
     public async getTransactionByHashAsync(txHash: string): Promise<Transaction> {
         assert.isHexString('txHash', txHash);
-        const transaction = await this.sendRawPayloadAsync<Transaction>({
+        const transactionRpc = await this.sendRawPayloadAsync<TransactionRPC>({
             method: 'eth_getTransactionByHash',
             params: [txHash],
         });
+        const transaction = marshaller.unmarshalTransaction(transactionRpc);
         return transaction;
     }
     /**
diff --git a/packages/website/md/docs/asset_buyer/installation.md b/packages/website/md/docs/asset_buyer/installation.md
index 76affaa09..3c0c95068 100644
--- a/packages/website/md/docs/asset_buyer/installation.md
+++ b/packages/website/md/docs/asset_buyer/installation.md
@@ -1,10 +1,10 @@
-**Install**
+#### Install
 
 ```bash
 yarn add @0x/asset-buyer
 ```
 
-**Import**
+#### Import
 
 ```javascript
 import { AssetBuyer } from '@0x/asset-buyer';
diff --git a/packages/website/md/docs/asset_buyer/usage.md b/packages/website/md/docs/asset_buyer/usage.md
index 6462d938e..209c15062 100644
--- a/packages/website/md/docs/asset_buyer/usage.md
+++ b/packages/website/md/docs/asset_buyer/usage.md
@@ -1,4 +1,4 @@
-**Construction**
+#### Construction
 
 Connecting to a standard relayer API compliant url:
 
@@ -16,7 +16,7 @@ const orders = []; // get these from your own API, a relayer, a friend, from any
 const assetBuyer = AssetBuyer.getAssetBuyerForProvidedOrders(provider, orders);
 ```
 
-**Get a quote**
+#### Get a quote
 
 A [BuyQuote](#types-BuyQuote) object contains enough information to display buy information to an end user
 
@@ -30,7 +30,7 @@ console.log(quoteInfo.feeAmount); // a portion of the total ethAmount above that
 console.log(quoteInfo.ethPerAssetPrice); // the rate that this quote provides (e.g. 0.0035ETH / REP)
 ```
 
-**Perform a buy**
+#### Perform a buy
 
 Pass the [BuyQuote](#types-BuyQuote) object from above back to the assetBuyer in order to initiate the buy transaction
 
diff --git a/packages/website/md/docs/json_schemas/2/schemas.md b/packages/website/md/docs/json_schemas/2/schemas.md
index ec7cf6f15..8ea6c8e85 100644
--- a/packages/website/md/docs/json_schemas/2/schemas.md
+++ b/packages/website/md/docs/json_schemas/2/schemas.md
@@ -1,40 +1,40 @@
 Basic Schemas
 
-*   [Address type](https://github.com/0xProject/0x-monorepo/blob/development/packages/json-schemas/schemas/address.json)
-*   [Number type](https://github.com/0xProject/0x-monorepo/blob/development/packages/json-schemas/schemas/number.json)
-*   [Hex type](https://github.com/0xProject/0x-monorepo/blob/development/packages/json-schemas/schemas/hex.json)
-*   [JS number](https://github.com/0xProject/0x-monorepo/blob/development/packages/json-schemas/schemas/js_number.json)
+*   [Address type](https://github.com/0xProject/0x-monorepo/blob/5ec4b27200297708298deca97603849a37b2f66a/packages/json-schemas/schemas/address_schema.json)
+*   [Number type](https://github.com/0xProject/0x-monorepo/blob/5ec4b27200297708298deca97603849a37b2f66a/packages/json-schemas/schemas/number_schema.json)
+*   [Hex type](https://github.com/0xProject/0x-monorepo/blob/5ec4b27200297708298deca97603849a37b2f66a/packages/json-schemas/schemas/hex_schema.json)
+*   [JS number](https://github.com/0xProject/0x-monorepo/blob/5ec4b27200297708298deca97603849a37b2f66a/packages/json-schemas/schemas/js_number.json)
 
 0x Protocol Schemas
 
-*   [Order](https://github.com/0xProject/0x-monorepo/blob/development/packages/json-schemas/schemas/order_schema.json)
-*   [SignedOrder](https://github.com/0xProject/0x-monorepo/blob/development/packages/json-schemas/schemas/signed_order_schema.json)
-*   [OrderHash](https://github.com/0xProject/0x-monorepo/blob/development/packages/json-schemas/schemas/order_hash_schema.json)
-*   [ECSignature](https://github.com/0xProject/0x-monorepo/blob/development/packages/json-schemas/schemas/ec_signature_schema.json)
+*   [Order](https://github.com/0xProject/0x-monorepo/blob/5ec4b27200297708298deca97603849a37b2f66a/packages/json-schemas/schemas/order_schema.json)
+*   [SignedOrder](https://github.com/0xProject/0x-monorepo/blob/5ec4b27200297708298deca97603849a37b2f66a/packages/json-schemas/schemas/signed_order_schema.json)
+*   [OrderHash](https://github.com/0xProject/0x-monorepo/blob/5ec4b27200297708298deca97603849a37b2f66a/packages/json-schemas/schemas/order_hash_schema.json)
+*   [ECSignature](https://github.com/0xProject/0x-monorepo/blob/5ec4b27200297708298deca97603849a37b2f66a/packages/json-schemas/schemas/ec_signature_schema.json)
 
 0x.js Schemas
 
-*   [BlockParam](https://github.com/0xProject/0x-monorepo/blob/development/packages/json-schemas/schemas/block_param_schema.json)
-*   [BlockRange](https://github.com/0xProject/0x-monorepo/blob/development/packages/json-schemas/schemas/block_range_schema.json)
-*   [IndexFilter Values](https://github.com/0xProject/0x-monorepo/blob/development/packages/json-schemas/schemas/index_filter_values_schema.json)
-*   [OrderFillRequests](https://github.com/0xProject/0x-monorepo/blob/development/packages/json-schemas/schemas/order_fill_requests_schema.json)
-*   [OrderCancellationRequests](https://github.com/0xProjet/0x-monorepo/blob/development/packages/json-schemas/schemas/order_cancel_schema.json)
-*   [OrderFillOrKillRequests](https://github.com/0xProject/0x-monorepo/blob/development/packages/json-schemas/schemas/order_fill_or_kill_requests_schema.json)
-*   [SignedOrders](https://github.com/0xProject/0x-monorepo/blob/development/packages/json-schemas/schemas/signed_orders_schema.json)
-*   [Token](https://github.com/0xProject/0x-monorepo/blob/development/packages/json-schemas/schemas/token_schema.json)
-*   [TxData](https://github.com/0xProject/0x-monorepo/blob/development/packages/json-schemas/schemas/tx_data_schema.json)
+*   [BlockParam](https://github.com/0xProject/0x-monorepo/blob/5ec4b27200297708298deca97603849a37b2f66a/packages/json-schemas/schemas/block_param_schema.json)
+*   [BlockRange](https://github.com/0xProject/0x-monorepo/blob/5ec4b27200297708298deca97603849a37b2f66a/packages/json-schemas/schemas/block_range_schema.json)
+*   [IndexFilter Values](https://github.com/0xProject/0x-monorepo/blob/5ec4b27200297708298deca97603849a37b2f66a/packages/json-schemas/schemas/index_filter_values_schema.json)
+*   [OrderFillRequests](https://github.com/0xProject/0x-monorepo/blob/5ec4b27200297708298deca97603849a37b2f66a/packages/json-schemas/schemas/order_fill_requests_schema.json)
+*   [OrderCancellationRequests](https://github.com/0xProject/0x-monorepo/blob/5ec4b27200297708298deca97603849a37b2f66a/packages/json-schemas/schemas/order_cancel_schema.json)
+*   [OrderFillOrKillRequests](https://github.com/0xProject/0x-monorepo/blob/5ec4b27200297708298deca97603849a37b2f66a/packages/json-schemas/schemas/order_fill_or_kill_requests_schema.json)
+*   [SignedOrders](https://github.com/0xProject/0x-monorepo/blob/5ec4b27200297708298deca97603849a37b2f66a/packages/json-schemas/schemas/signed_orders_schema.json)
+*   [Token](https://github.com/0xProject/0x-monorepo/blob/5ec4b27200297708298deca97603849a37b2f66a/packages/json-schemas/schemas/token_schema.json)
+*   [TxData](https://github.com/0xProject/0x-monorepo/blob/5ec4b27200297708298deca97603849a37b2f66a/packages/json-schemas/schemas/tx_data_schema.json)
 
 Standard Relayer API Schemas
 
-*   [Paginated collection](https://github.com/0xProject/0x-monorepo/blob/development/packages/json-schemas/schemas/paginated_collection_schema.json)
-*   [Error response](https://github.com/0xProject/0x-monorepo/blob/development/packages/json-schemas/schemas/relayer_api_error_response_schema.json)
-*   [Order config payload](https://github.com/0xProject/0x-monorepo/blob/development/packages/json-schemas/schemas/relayer_api_order_config_payload_schema.json)
-*   [Order config response](https://github.com/0xProject/0x-monorepo/blob/development/packages/json-schemas/schemas/relayer_api_order_config_response_schema.json)
-*   [Orders channel subscribe payload](https://github.com/0xProject/0x-monorepo/blob/development/packages/json-schemas/schemas/relayer_api_orders_channel_subscribe_payload_schema.json)
-*   [Orders channel subscribe](https://github.com/0xProject/0x-monorepo/blob/development/packages/json-schemas/schemas/relayer_api_orders_channel_subscribe_schema.json)
-*   [Orders channel update](https://github.com/0xProject/0x-monorepo/blob/development/packages/json-schemas/schemas/relayer_api_orders_channel_update_response_schema.json)
-*   [Orderbook response](https://github.com/0xProject/0x-monorepo/blob/development/packages/json-schemas/schemas/relayer_api_orderbook_response_schema.json)
-*   [Asset pairs](https://github.com/0xProject/0x-monorepo/blob/development/packages/json-schemas/schemas/relayer_api_asset_pairs_schema.json)
-*   [Trade info](https://github.com/0xProject/0x-monorepo/blob/development/packages/json-schemas/schemas/relayer_api_asset_trade_info_schema.json)
-*   [Asset pairs response](https://github.com/0xProject/0x-monorepo/blob/development/packages/json-schemas/schemas/relayer_api_asset_pairs_response_schema.json)
-*   [Fee recipients response](https://github.com/0xProject/0x-monorepo/blob/development/packages/json-schemas/schemas/relayer_api_fee_recipients_response_schema.json)
+*   [Paginated collection](https://github.com/0xProject/0x-monorepo/blob/5ec4b27200297708298deca97603849a37b2f66a/packages/json-schemas/schemas/paginated_collection_schema.json)
+*   [Error response](https://github.com/0xProject/0x-monorepo/blob/5ec4b27200297708298deca97603849a37b2f66a/packages/json-schemas/schemas/relayer_api_error_response_schema.json)
+*   [Order config payload](https://github.com/0xProject/0x-monorepo/blob/5ec4b27200297708298deca97603849a37b2f66a/packages/json-schemas/schemas/relayer_api_order_config_payload_schema.json)
+*   [Order config response](https://github.com/0xProject/0x-monorepo/blob/5ec4b27200297708298deca97603849a37b2f66a/packages/json-schemas/schemas/relayer_api_order_config_response_schema.json)
+*   [Orders channel subscribe payload](https://github.com/0xProject/0x-monorepo/blob/5ec4b27200297708298deca97603849a37b2f66a/packages/json-schemas/schemas/relayer_api_orders_channel_subscribe_payload_schema.json)
+*   [Orders channel subscribe](https://github.com/0xProject/0x-monorepo/blob/5ec4b27200297708298deca97603849a37b2f66a/packages/json-schemas/schemas/relayer_api_orders_channel_subscribe_schema.json)
+*   [Orders channel update](https://github.com/0xProject/0x-monorepo/blob/5ec4b27200297708298deca97603849a37b2f66a/packages/json-schemas/schemas/relayer_api_orders_channel_update_response_schema.json)
+*   [Orderbook response](https://github.com/0xProject/0x-monorepo/blob/5ec4b27200297708298deca97603849a37b2f66a/packages/json-schemas/schemas/relayer_api_orderbook_response_schema.json)
+*   [Asset pairs](https://github.com/0xProject/0x-monorepo/blob/5ec4b27200297708298deca97603849a37b2f66a/packages/json-schemas/schemas/relayer_api_asset_data_pairs_schema.json)
+*   [Trade info](https://github.com/0xProject/0x-monorepo/blob/5ec4b27200297708298deca97603849a37b2f66a/packages/json-schemas/schemas/relayer_api_asset_data_trade_info_schema.json)
+*   [Asset pairs response](https://github.com/0xProject/0x-monorepo/blob/5ec4b27200297708298deca97603849a37b2f66a/packages/json-schemas/schemas/relayer_api_asset_data_pairs_response_schema.json)
+*   [Fee recipients response](https://github.com/0xProject/0x-monorepo/blob/5ec4b27200297708298deca97603849a37b2f66a/packages/json-schemas/schemas/relayer_api_fee_recipients_response_schema.json)
diff --git a/packages/website/md/docs/json_schemas/3/schemas.md b/packages/website/md/docs/json_schemas/3/schemas.md
new file mode 100644
index 000000000..99aff7b5a
--- /dev/null
+++ b/packages/website/md/docs/json_schemas/3/schemas.md
@@ -0,0 +1,41 @@
+Basic Schemas
+
+*   [Address type](https://github.com/0xProject/0x-monorepo/blob/528ae4376e5e605dac9666f2a5917803e942a1f9/packages/json-schemas/schemas/address_schema.json)
+*   [Number type](https://github.com/0xProject/0x-monorepo/blob/528ae4376e5e605dac9666f2a5917803e942a1f9/packages/json-schemas/schemas/number_schema.json)
+*   [Whole number type](https://github.com/0xProject/0x-monorepo/blob/528ae4376e5e605dac9666f2a5917803e942a1f9/packages/json-schemas/schemas/whole_number_schema.json)
+*   [Hex type](https://github.com/0xProject/0x-monorepo/blob/528ae4376e5e605dac9666f2a5917803e942a1f9/packages/json-schemas/schemas/hex_schema.json)
+*   [JS number](https://github.com/0xProject/0x-monorepo/blob/528ae4376e5e605dac9666f2a5917803e942a1f9/packages/json-schemas/schemas/js_number.json)
+
+0x Protocol Schemas
+
+*   [Order](https://github.com/0xProject/0x-monorepo/blob/528ae4376e5e605dac9666f2a5917803e942a1f9/packages/json-schemas/schemas/order_schema.json)
+*   [SignedOrder](https://github.com/0xProject/0x-monorepo/blob/528ae4376e5e605dac9666f2a5917803e942a1f9/packages/json-schemas/schemas/signed_order_schema.json)
+*   [OrderHash](https://github.com/0xProject/0x-monorepo/blob/528ae4376e5e605dac9666f2a5917803e942a1f9/packages/json-schemas/schemas/order_hash_schema.json)
+*   [ECSignature](https://github.com/0xProject/0x-monorepo/blob/528ae4376e5e605dac9666f2a5917803e942a1f9/packages/json-schemas/schemas/ec_signature_schema.json)
+
+0x.js Schemas
+
+*   [BlockParam](https://github.com/0xProject/0x-monorepo/blob/528ae4376e5e605dac9666f2a5917803e942a1f9/packages/json-schemas/schemas/block_param_schema.json)
+*   [BlockRange](https://github.com/0xProject/0x-monorepo/blob/528ae4376e5e605dac9666f2a5917803e942a1f9/packages/json-schemas/schemas/block_range_schema.json)
+*   [IndexFilter Values](https://github.com/0xProject/0x-monorepo/blob/528ae4376e5e605dac9666f2a5917803e942a1f9/packages/json-schemas/schemas/index_filter_values_schema.json)
+*   [OrderFillRequests](https://github.com/0xProject/0x-monorepo/blob/528ae4376e5e605dac9666f2a5917803e942a1f9/packages/json-schemas/schemas/order_fill_requests_schema.json)
+*   [OrderCancellationRequests](https://github.com/0xProject/0x-monorepo/blob/528ae4376e5e605dac9666f2a5917803e942a1f9/packages/json-schemas/schemas/order_cancel_schema.json)
+*   [OrderFillOrKillRequests](https://github.com/0xProject/0x-monorepo/blob/528ae4376e5e605dac9666f2a5917803e942a1f9/packages/json-schemas/schemas/order_fill_or_kill_requests_schema.json)
+*   [SignedOrders](https://github.com/0xProject/0x-monorepo/blob/528ae4376e5e605dac9666f2a5917803e942a1f9/packages/json-schemas/schemas/signed_orders_schema.json)
+*   [Token](https://github.com/0xProject/0x-monorepo/blob/528ae4376e5e605dac9666f2a5917803e942a1f9/packages/json-schemas/schemas/token_schema.json)
+*   [TxData](https://github.com/0xProject/0x-monorepo/blob/528ae4376e5e605dac9666f2a5917803e942a1f9/packages/json-schemas/schemas/tx_data_schema.json)
+
+Standard Relayer API Schemas
+
+*   [Paginated collection](https://github.com/0xProject/0x-monorepo/blob/528ae4376e5e605dac9666f2a5917803e942a1f9/packages/json-schemas/schemas/paginated_collection_schema.json)
+*   [Error response](https://github.com/0xProject/0x-monorepo/blob/528ae4376e5e605dac9666f2a5917803e942a1f9/packages/json-schemas/schemas/relayer_api_error_response_schema.json)
+*   [Order config payload](https://github.com/0xProject/0x-monorepo/blob/528ae4376e5e605dac9666f2a5917803e942a1f9/packages/json-schemas/schemas/relayer_api_order_config_payload_schema.json)
+*   [Order config response](https://github.com/0xProject/0x-monorepo/blob/528ae4376e5e605dac9666f2a5917803e942a1f9/packages/json-schemas/schemas/relayer_api_order_config_response_schema.json)
+*   [Orders channel subscribe payload](https://github.com/0xProject/0x-monorepo/blob/528ae4376e5e605dac9666f2a5917803e942a1f9/packages/json-schemas/schemas/relayer_api_orders_channel_subscribe_payload_schema.json)
+*   [Orders channel subscribe](https://github.com/0xProject/0x-monorepo/blob/528ae4376e5e605dac9666f2a5917803e942a1f9/packages/json-schemas/schemas/relayer_api_orders_channel_subscribe_schema.json)
+*   [Orders channel update](https://github.com/0xProject/0x-monorepo/blob/528ae4376e5e605dac9666f2a5917803e942a1f9/packages/json-schemas/schemas/relayer_api_orders_channel_update_response_schema.json)
+*   [Orderbook response](https://github.com/0xProject/0x-monorepo/blob/528ae4376e5e605dac9666f2a5917803e942a1f9/packages/json-schemas/schemas/relayer_api_orderbook_response_schema.json)
+*   [Asset pairs](https://github.com/0xProject/0x-monorepo/blob/528ae4376e5e605dac9666f2a5917803e942a1f9/packages/json-schemas/schemas/relayer_api_asset_data_pairs_schema.json)
+*   [Trade info](https://github.com/0xProject/0x-monorepo/blob/528ae4376e5e605dac9666f2a5917803e942a1f9/packages/json-schemas/schemas/relayer_api_asset_data_trade_info_schema.json)
+*   [Asset pairs response](https://github.com/0xProject/0x-monorepo/blob/528ae4376e5e605dac9666f2a5917803e942a1f9/packages/json-schemas/schemas/relayer_api_asset_data_pairs_response_schema.json)
+*   [Fee recipients response](https://github.com/0xProject/0x-monorepo/blob/528ae4376e5e605dac9666f2a5917803e942a1f9/packages/json-schemas/schemas/relayer_api_fee_recipients_response_schema.json)
diff --git a/packages/website/ts/blockchain.ts b/packages/website/ts/blockchain.ts
index efb5aef23..62e16dd1d 100644
--- a/packages/website/ts/blockchain.ts
+++ b/packages/website/ts/blockchain.ts
@@ -163,7 +163,7 @@ export class Blockchain {
             const providerName = this._getNameGivenProvider(injectedWeb3.currentProvider);
             // Wrap Metamask in a compatability wrapper MetamaskSubprovider (to handle inconsistencies)
             const signerSubprovider =
-                providerName === Providers.Metamask
+                providerName === constants.PROVIDER_NAME_METAMASK
                     ? new MetamaskSubprovider(injectedWeb3.currentProvider)
                     : new SignerSubprovider(injectedWeb3.currentProvider);
             provider.addProvider(signerSubprovider);
diff --git a/packages/website/ts/components/portal/portal.tsx b/packages/website/ts/components/portal/portal.tsx
index 2299881c4..94ab63ac6 100644
--- a/packages/website/ts/components/portal/portal.tsx
+++ b/packages/website/ts/components/portal/portal.tsx
@@ -210,12 +210,16 @@ export class Portal extends React.Component<PortalProps, PortalState> {
                     isLoaded: false,
                 };
             }
-            this.setState({
-                trackedTokenStateByAddress,
-            });
-            // Fetch the actual balance/allowance.
-            // tslint:disable-next-line:no-floating-promises
-            this._fetchBalancesAndAllowancesAsync(newTokenAddresses);
+            this.setState(
+                {
+                    trackedTokenStateByAddress,
+                },
+                () => {
+                    // Fetch the actual balance/allowance.
+                    // tslint:disable-next-line:no-floating-promises
+                    this._fetchBalancesAndAllowancesAsync(newTokenAddresses);
+                },
+            );
         }
     }
     public render(): React.ReactNode {
@@ -644,6 +648,9 @@ export class Portal extends React.Component<PortalProps, PortalState> {
     }
 
     private async _fetchBalancesAndAllowancesAsync(tokenAddresses: string[]): Promise<void> {
+        if (_.isEmpty(tokenAddresses)) {
+            return;
+        }
         const trackedTokenStateByAddress = this.state.trackedTokenStateByAddress;
         const userAddressIfExists = _.isEmpty(this.props.userAddress) ? undefined : this.props.userAddress;
         const balancesAndAllowances = await Promise.all(
diff --git a/packages/website/ts/containers/json_schemas_documentation.ts b/packages/website/ts/containers/json_schemas_documentation.ts
index cb5918784..9c4bb8e26 100644
--- a/packages/website/ts/containers/json_schemas_documentation.ts
+++ b/packages/website/ts/containers/json_schemas_documentation.ts
@@ -15,8 +15,9 @@ const InstallationMarkdown1 = require('md/docs/json_schemas/1/installation');
 const InstallationMarkdown3 = require('md/docs/json_schemas/3/installation');
 const usageMarkdown1 = require('md/docs/json_schemas/1/usage');
 const usageMarkdown3 = require('md/docs/json_schemas/3/usage');
-const SchemasMarkdownV1 = require('md/docs/json_schemas/1/schemas');
-const SchemasMarkdownV2 = require('md/docs/json_schemas/2/schemas');
+const SchemasMarkdown1 = require('md/docs/json_schemas/1/schemas');
+const SchemasMarkdown2 = require('md/docs/json_schemas/2/schemas');
+const SchemasMarkdown3 = require('md/docs/json_schemas/3/schemas');
 /* tslint:enable:no-var-requires */
 
 const markdownSections = {
@@ -40,19 +41,25 @@ const docsInfoConfig: DocsInfoConfig = {
         '0.0.1': {
             [markdownSections.introduction]: IntroMarkdown1,
             [markdownSections.installation]: InstallationMarkdown1,
-            [markdownSections.schemas]: SchemasMarkdownV1,
+            [markdownSections.schemas]: SchemasMarkdown1,
             [markdownSections.usage]: usageMarkdown1,
         },
         '1.0.0': {
             [markdownSections.introduction]: IntroMarkdown1,
             [markdownSections.installation]: InstallationMarkdown1,
-            [markdownSections.schemas]: SchemasMarkdownV2,
+            [markdownSections.schemas]: SchemasMarkdown2,
             [markdownSections.usage]: usageMarkdown1,
         },
         '2.0.0': {
             [markdownSections.introduction]: IntroMarkdown3,
             [markdownSections.installation]: InstallationMarkdown3,
-            [markdownSections.schemas]: SchemasMarkdownV2,
+            [markdownSections.schemas]: SchemasMarkdown2,
+            [markdownSections.usage]: usageMarkdown3,
+        },
+        '2.0.1': {
+            [markdownSections.introduction]: IntroMarkdown3,
+            [markdownSections.installation]: InstallationMarkdown3,
+            [markdownSections.schemas]: SchemasMarkdown3,
             [markdownSections.usage]: usageMarkdown3,
         },
     },
diff --git a/python-packages/order_utils/setup.py b/python-packages/order_utils/setup.py
index a76d724aa..1a094cfe1 100644..100755
--- a/python-packages/order_utils/setup.py
+++ b/python-packages/order_utils/setup.py
@@ -1,13 +1,16 @@
+#!/usr/bin/env python
+
 """setuptools module for order_utils package."""
 
 import subprocess  # nosec
 from shutil import rmtree
-from os import path, remove, walk
+from os import environ, path, remove, walk
+from sys import argv
 
-from distutils.command.clean import clean  # type: ignore
-from setuptools import setup  # type: ignore
-import setuptools.command.build_py  # type: ignore
-from setuptools.command.test import test as TestCommand  # type: ignore
+from distutils.command.clean import clean
+import distutils.command.build_py
+from setuptools import setup
+from setuptools.command.test import test as TestCommand
 
 
 class TestCommandExtension(TestCommand):
@@ -15,13 +18,13 @@ class TestCommandExtension(TestCommand):
 
     def run_tests(self):
         """Invoke pytest."""
-        import pytest  # type: ignore
+        import pytest
 
         pytest.main()
 
 
 # pylint: disable=too-many-ancestors
-class LintCommand(setuptools.command.build_py.build_py):
+class LintCommand(distutils.command.build_py.build_py):
     """Custom setuptools command class for running linters."""
 
     def run(self):
@@ -34,7 +37,7 @@ class LintCommand(setuptools.command.build_py.build_py):
             # docstring style checker:
             "pydocstyle src test setup.py".split(),
             # static type checker:
-            "mypy src setup.py".split(),
+            "mypy src test setup.py".split(),
             # security issue checker:
             "bandit -r src ./setup.py".split(),
             # general linter:
@@ -42,6 +45,21 @@ class LintCommand(setuptools.command.build_py.build_py):
             # pylint takes relatively long to run, so it runs last, to enable
             # fast failures.
         ]
+
+        # tell mypy where to find interface stubs for 3rd party libs
+        environ["MYPYPATH"] = path.join(
+            path.dirname(path.realpath(argv[0])), "stubs"
+        )
+
+        # HACK(gene): until eth_abi releases
+        # https://github.com/ethereum/eth-abi/pull/107 , we need to simply
+        # create an empty file `py.typed` in the eth_abi package directory.
+        import eth_abi
+
+        eth_abi_dir = path.dirname(path.realpath(eth_abi.__file__))
+        with open(path.join(eth_abi_dir, "py.typed"), "a"):
+            pass
+
         for lint_command in lint_commands:
             print(
                 "Running lint command `", " ".join(lint_command).strip(), "`"
@@ -79,7 +97,7 @@ setup(
         "test": TestCommandExtension,
     },
     include_package_data=True,
-    install_requires=["web3"],
+    install_requires=["eth-abi", "web3"],
     extras_require={
         "dev": [
             "bandit",
@@ -87,6 +105,7 @@ setup(
             "coverage",
             "coveralls",
             "mypy",
+            "mypy_extensions",
             "pycodestyle",
             "pydocstyle",
             "pylint",
@@ -118,7 +137,7 @@ setup(
         "Topic :: Software Development :: Libraries",
         "Topic :: Utilities",
     ],
-    zip_safe=False,
+    zip_safe=False,  # required per mypy
     command_options={
         "build_sphinx": {
             "source_dir": ("setup.py", "src"),
diff --git a/python-packages/order_utils/src/conf.py b/python-packages/order_utils/src/conf.py
index f3f15967c..e74a29d00 100644
--- a/python-packages/order_utils/src/conf.py
+++ b/python-packages/order_utils/src/conf.py
@@ -2,6 +2,9 @@
 
 # Reference: http://www.sphinx-doc.org/en/master/config
 
+from typing import List
+
+
 # pylint: disable=invalid-name
 # because these variables are not named in upper case, as globals should be.
 
@@ -29,7 +32,7 @@ master_doc = "index"  # The master toctree document.
 
 language = None
 
-exclude_patterns = []  # type: ignore
+exclude_patterns: List[str] = []
 
 # The name of the Pygments (syntax highlighting) style to use.
 pygments_style = None
diff --git a/python-packages/order_utils/src/index.rst b/python-packages/order_utils/src/index.rst
index cbc4c8409..e09abcca2 100644
--- a/python-packages/order_utils/src/index.rst
+++ b/python-packages/order_utils/src/index.rst
@@ -10,9 +10,12 @@ order_utils.py
 .. automodule:: zero_ex.order_utils
    :members:
 
-.. automodule:: zero_ex.order_utils.signature_utils
+.. automodule:: zero_ex.order_utils.asset_data_utils
    :members:
 
+.. autoclass:: zero_ex.order_utils.asset_data_utils.ERC20AssetData
+
+See source for properties.  Sphinx does not easily generate class property docs; pull requests welcome.
 
 Indices and tables
 ==================
diff --git a/python-packages/order_utils/src/zero_ex/dev_utils/__init__.py b/python-packages/order_utils/src/zero_ex/dev_utils/__init__.py
new file mode 100644
index 000000000..b6a224d2c
--- /dev/null
+++ b/python-packages/order_utils/src/zero_ex/dev_utils/__init__.py
@@ -0,0 +1 @@
+"""Dev utils to be shared across 0x projects and packages."""
diff --git a/python-packages/order_utils/src/zero_ex/dev_utils/abi_utils.py b/python-packages/order_utils/src/zero_ex/dev_utils/abi_utils.py
new file mode 100644
index 000000000..71b6128ca
--- /dev/null
+++ b/python-packages/order_utils/src/zero_ex/dev_utils/abi_utils.py
@@ -0,0 +1,102 @@
+"""Ethereum ABI utilities.
+
+Builds on the eth-abi package, adding some convenience methods like those found
+in npmjs.com/package/ethereumjs-abi.  Ideally, all of this code should be
+pushed upstream into eth-abi.
+"""
+
+import re
+from typing import Any, List
+
+from mypy_extensions import TypedDict
+
+from eth_abi import encode_abi
+from web3 import Web3
+
+from .type_assertions import assert_is_string, assert_is_list
+
+
+class MethodSignature(TypedDict, total=False):
+    """Object interface to an ABI method signature."""
+
+    method: str
+    args: List[str]
+
+
+def parse_signature(signature: str) -> MethodSignature:
+    """Parse a method signature into its constituent parts.
+
+    >>> parse_signature("ERC20Token(address)")
+    {'method': 'ERC20Token', 'args': ['address']}
+    """
+    assert_is_string(signature, "signature")
+
+    matches = re.match(r"^(\w+)\((.+)\)$", signature)
+    if matches is None:
+        raise ValueError(f"Invalid method signature {signature}")
+    return {"method": matches[1], "args": matches[2].split(",")}
+
+
+def elementary_name(name: str) -> str:
+    """Convert from short to canonical names; barely implemented.
+
+    Modeled after ethereumjs-abi's ABI.elementaryName(), but only implemented
+    to support our particular use case and a few other simple ones.
+
+    >>> elementary_name("address")
+    'address'
+    >>> elementary_name("uint")
+    'uint256'
+    """
+    assert_is_string(name, "name")
+
+    return {
+        "int": "int256",
+        "uint": "uint256",
+        "fixed": "fixed128x128",
+        "ufixed": "ufixed128x128",
+    }.get(name, name)
+
+
+def event_id(name: str, types: List[str]) -> str:
+    """Return the Keccak-256 hash of the given method.
+
+    >>> event_id("ERC20Token", ["address"])
+    '0xf47261b06eedbfce68afd46d0f3c27c60b03faad319eaf33103611cf8f6456ad'
+    """
+    assert_is_string(name, "name")
+    assert_is_list(types, "types")
+
+    signature = f"{name}({','.join(list(map(elementary_name, types)))})"
+    return Web3.sha3(text=signature).hex()
+
+
+def method_id(name: str, types: List[str]) -> str:
+    """Return the 4-byte method identifier.
+
+    >>> method_id("ERC20Token", ["address"])
+    '0xf47261b0'
+    """
+    assert_is_string(name, "name")
+    assert_is_list(types, "types")
+
+    return event_id(name, types)[0:10]
+
+
+def simple_encode(method: str, *args: Any) -> bytes:
+    # docstring considered all one line by pylint: disable=line-too-long
+    r"""Encode a method ABI.
+
+    >>> simple_encode("ERC20Token(address)", "0x1dc4c1cefef38a777b15aa20260a54e584b16c48")
+    b'\xf4ra\xb0\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x1d\xc4\xc1\xce\xfe\xf3\x8aw{\x15\xaa &\nT\xe5\x84\xb1lH'
+    """  # noqa: E501 (line too long)
+    assert_is_string(method, "method")
+
+    signature: MethodSignature = parse_signature(method)
+
+    return bytes.fromhex(
+        (
+            method_id(signature["method"], signature["args"])
+            + encode_abi(signature["args"], args).hex()
+        )[2:]
+    )
diff --git a/python-packages/order_utils/src/zero_ex/dev_utils/type_assertions.py b/python-packages/order_utils/src/zero_ex/dev_utils/type_assertions.py
new file mode 100644
index 000000000..745d014e6
--- /dev/null
+++ b/python-packages/order_utils/src/zero_ex/dev_utils/type_assertions.py
@@ -0,0 +1,33 @@
+"""Assertions for runtime type checking of function arguments."""
+
+from typing import Any
+
+
+def assert_is_string(value: Any, name: str) -> None:
+    """If :param value: isn't of type str, raise a TypeError.
+
+    >>> try: assert_is_string(123, 'var')
+    ... except TypeError as type_error: print(str(type_error))
+    ...
+    expected variable 'var', with value 123, to have type 'str', not 'int'
+    """
+    if not isinstance(value, str):
+        raise TypeError(
+            f"expected variable '{name}', with value {str(value)}, to have"
+            + f" type 'str', not '{type(value).__name__}'"
+        )
+
+
+def assert_is_list(value: Any, name: str) -> None:
+    """If :param value: isn't of type list, raise a TypeError.
+
+    >>> try: assert_is_list(123, 'var')
+    ... except TypeError as type_error: print(str(type_error))
+    ...
+    expected variable 'var', with value 123, to have type 'list', not 'int'
+    """
+    if not isinstance(value, list):
+        raise TypeError(
+            f"expected variable '{name}', with value {str(value)}, to have"
+            + f" type 'list', not '{type(value).__name__}'"
+        )
diff --git a/python-packages/order_utils/src/zero_ex/order_utils/asset_data_utils.py b/python-packages/order_utils/src/zero_ex/order_utils/asset_data_utils.py
new file mode 100644
index 000000000..451de39af
--- /dev/null
+++ b/python-packages/order_utils/src/zero_ex/order_utils/asset_data_utils.py
@@ -0,0 +1,72 @@
+"""Asset data encoding and decoding utilities."""
+
+from mypy_extensions import TypedDict
+
+import eth_abi
+
+from zero_ex.dev_utils import abi_utils
+from zero_ex.dev_utils.type_assertions import assert_is_string
+
+
+ERC20_ASSET_DATA_BYTE_LENGTH = 36
+SELECTOR_LENGTH = 10
+
+
+class ERC20AssetData(TypedDict):
+    """Object interface to ERC20 asset data."""
+
+    asset_proxy_id: str
+    token_address: str
+
+
+def encode_erc20_asset_data(token_address: str) -> str:
+    """Encode an ERC20 token address into an asset data string.
+
+    :param token_address: the ERC20 token's contract address.
+    :rtype: hex encoded asset data string, usable in the makerAssetData or
+        takerAssetData fields in a 0x order.
+
+    >>> encode_erc20_asset_data('0x1dc4c1cefef38a777b15aa20260a54e584b16c48')
+    '0xf47261b00000000000000000000000001dc4c1cefef38a777b15aa20260a54e584b16c48'
+    """
+    assert_is_string(token_address, "token_address")
+
+    return (
+        "0x"
+        + abi_utils.simple_encode("ERC20Token(address)", token_address).hex()
+    )
+
+
+def decode_erc20_asset_data(asset_data: str) -> ERC20AssetData:
+    # docstring considered all one line by pylint: disable=line-too-long
+    """Decode an ERC20 assetData hex string.
+
+    :param asset_data: String produced by prior call to encode_erc20_asset_data()
+
+    >>> decode_erc20_asset_data("0xf47261b00000000000000000000000001dc4c1cefef38a777b15aa20260a54e584b16c48")
+    {'asset_proxy_id': '0xf47261b0', 'token_address': '0x1dc4c1cefef38a777b15aa20260a54e584b16c48'}
+    """  # noqa: E501 (line too long)
+    assert_is_string(asset_data, "asset_data")
+
+    if len(asset_data) < ERC20_ASSET_DATA_BYTE_LENGTH:
+        raise ValueError(
+            "Could not decode ERC20 Proxy Data. Expected length of encoded"
+            + f" data to be at least {str(ERC20_ASSET_DATA_BYTE_LENGTH)}."
+            + f" Got {str(len(asset_data))}."
+        )
+
+    asset_proxy_id: str = asset_data[0:10]
+    if asset_proxy_id != abi_utils.method_id("ERC20Token", ["address"]):
+        raise ValueError(
+            "Could not decode ERC20 Proxy Data. Expected Asset Proxy Id to be"
+            + f" ERC20 ({abi_utils.method_id('ERC20Token', ['address'])})"
+            + f" but got {asset_proxy_id}."
+        )
+
+    # workaround for https://github.com/PyCQA/pylint/issues/1498
+    # pylint: disable=unsubscriptable-object
+    token_address = eth_abi.decode_abi(
+        ["address"], bytes.fromhex(asset_data[SELECTOR_LENGTH:])
+    )[0]
+
+    return {"asset_proxy_id": asset_proxy_id, "token_address": token_address}
diff --git a/python-packages/order_utils/src/zero_ex/order_utils/signature_utils.py b/python-packages/order_utils/src/zero_ex/order_utils/signature_utils.py
deleted file mode 100644
index 7f4697106..000000000
--- a/python-packages/order_utils/src/zero_ex/order_utils/signature_utils.py
+++ /dev/null
@@ -1,13 +0,0 @@
-"""Signature utilities."""
-
-
-def ec_sign_order_hash():
-    """Signs an orderHash.
-
-    Returns its elliptic curve signature and signature type.  This method
-    currently supports TestRPC, Geth, and Parity above and below v1.6.6.
-
-    >>> ec_sign_order_hash()
-    'stub return value'
-    """
-    return "stub return value"
diff --git a/python-packages/order_utils/stubs/distutils/__init__.pyi b/python-packages/order_utils/stubs/distutils/__init__.pyi
new file mode 100644
index 000000000..e69de29bb
--- /dev/null
+++ b/python-packages/order_utils/stubs/distutils/__init__.pyi
diff --git a/python-packages/order_utils/stubs/distutils/command/__init__.pyi b/python-packages/order_utils/stubs/distutils/command/__init__.pyi
new file mode 100644
index 000000000..e69de29bb
--- /dev/null
+++ b/python-packages/order_utils/stubs/distutils/command/__init__.pyi
diff --git a/python-packages/order_utils/stubs/distutils/command/clean.pyi b/python-packages/order_utils/stubs/distutils/command/clean.pyi
new file mode 100644
index 000000000..46a42ddb1
--- /dev/null
+++ b/python-packages/order_utils/stubs/distutils/command/clean.pyi
@@ -0,0 +1,7 @@
+from distutils.core import Command
+
+class clean(Command):
+    def initialize_options(self: clean) -> None: ...
+    def finalize_options(self: clean) -> None: ...
+    def run(self: clean) -> None: ...
+    ...
diff --git a/python-packages/order_utils/stubs/pytest/__init__.pyi b/python-packages/order_utils/stubs/pytest/__init__.pyi
new file mode 100644
index 000000000..e69de29bb
--- /dev/null
+++ b/python-packages/order_utils/stubs/pytest/__init__.pyi
diff --git a/python-packages/order_utils/stubs/pytest/raises.pyi b/python-packages/order_utils/stubs/pytest/raises.pyi
new file mode 100644
index 000000000..2e3b29f3d
--- /dev/null
+++ b/python-packages/order_utils/stubs/pytest/raises.pyi
@@ -0,0 +1 @@
+def raises(exception: Exception) -> ExceptionInfo: ...
diff --git a/python-packages/order_utils/stubs/setuptools/__init__.pyi b/python-packages/order_utils/stubs/setuptools/__init__.pyi
new file mode 100644
index 000000000..baa349d70
--- /dev/null
+++ b/python-packages/order_utils/stubs/setuptools/__init__.pyi
@@ -0,0 +1,6 @@
+from distutils.dist import Distribution
+from typing import Any
+
+def setup(**attrs: Any) -> Distribution: ...
+
+class Command: ...
diff --git a/python-packages/order_utils/stubs/setuptools/command/__init__.pyi b/python-packages/order_utils/stubs/setuptools/command/__init__.pyi
new file mode 100644
index 000000000..e69de29bb
--- /dev/null
+++ b/python-packages/order_utils/stubs/setuptools/command/__init__.pyi
diff --git a/python-packages/order_utils/stubs/setuptools/command/test.pyi b/python-packages/order_utils/stubs/setuptools/command/test.pyi
new file mode 100644
index 000000000..c5ec770ad
--- /dev/null
+++ b/python-packages/order_utils/stubs/setuptools/command/test.pyi
@@ -0,0 +1,3 @@
+from setuptools import Command
+
+class test(Command): ...
diff --git a/python-packages/order_utils/stubs/web3/__init__.pyi b/python-packages/order_utils/stubs/web3/__init__.pyi
new file mode 100644
index 000000000..c6f357009
--- /dev/null
+++ b/python-packages/order_utils/stubs/web3/__init__.pyi
@@ -0,0 +1,10 @@
+from typing import Optional, Union
+
+class Web3:
+    @staticmethod
+    def sha3(
+        primitive: Optional[Union[bytes, int, None]] = None,
+        text: Optional[str] = None,
+        hexstr: Optional[str] = None
+    ) -> bytes: ...
+    ...
diff --git a/python-packages/order_utils/test/test_abi_utils.py b/python-packages/order_utils/test/test_abi_utils.py
new file mode 100644
index 000000000..49a2a4f20
--- /dev/null
+++ b/python-packages/order_utils/test/test_abi_utils.py
@@ -0,0 +1,53 @@
+"""Tests of 0x.abi_utils."""
+
+import pytest
+
+from zero_ex.dev_utils.abi_utils import (
+    elementary_name,
+    event_id,
+    method_id,
+    parse_signature,
+    simple_encode,
+)
+
+
+def test_parse_signature_type_error():
+    """Test that passing in wrong types raises TypeError."""
+    with pytest.raises(TypeError):
+        parse_signature(123)
+
+
+def test_parse_signature_bad_input():
+    """Test that passing a non-signature string raises a ValueError."""
+    with pytest.raises(ValueError):
+        parse_signature("a string that's not even close to a signature")
+
+
+def test_elementary_name_type_error():
+    """Test that passing in wrong types raises TypeError."""
+    with pytest.raises(TypeError):
+        elementary_name(123)
+
+
+def test_event_id_type_error():
+    """Test that passing in wrong types raises TypeError."""
+    with pytest.raises(TypeError):
+        event_id(123, [])
+
+    with pytest.raises(TypeError):
+        event_id("valid string", 123)
+
+
+def test_method_id_type_error():
+    """Test that passing in wrong types raises TypeError."""
+    with pytest.raises(TypeError):
+        method_id(123, [])
+
+    with pytest.raises(TypeError):
+        method_id("ERC20Token", 123)
+
+
+def test_simple_encode_type_error():
+    """Test that passing in wrong types raises TypeError."""
+    with pytest.raises(TypeError):
+        simple_encode(123)
diff --git a/python-packages/order_utils/test/test_asset_data_utils.py b/python-packages/order_utils/test/test_asset_data_utils.py
new file mode 100644
index 000000000..eeada5873
--- /dev/null
+++ b/python-packages/order_utils/test/test_asset_data_utils.py
@@ -0,0 +1,35 @@
+"""Tests of 0x.order_utils.asset_data_utils."""
+
+import pytest
+
+from zero_ex.order_utils.asset_data_utils import (
+    encode_erc20_asset_data,
+    decode_erc20_asset_data,
+    ERC20_ASSET_DATA_BYTE_LENGTH,
+)
+
+
+def test_encode_erc20_asset_data_type_error():
+    """Test that passing in a non-string raises a TypeError."""
+    with pytest.raises(TypeError):
+        encode_erc20_asset_data(123)
+
+
+def test_decode_erc20_asset_data_type_error():
+    """Test that passing in a non-string raises a TypeError."""
+    with pytest.raises(TypeError):
+        decode_erc20_asset_data(123)
+
+
+def test_decode_erc20_asset_data_too_short():
+    """Test that passing an insufficiently long string raises a ValueError."""
+    with pytest.raises(ValueError):
+        decode_erc20_asset_data(" " * (ERC20_ASSET_DATA_BYTE_LENGTH - 1))
+
+
+def test_decode_erc20_asset_data_invalid_proxy_id():
+    """Test that passing data with an invalid proxy ID raises a ValueError."""
+    with pytest.raises(ValueError):
+        decode_erc20_asset_data(
+            "0xffffffff" + (" " * ERC20_ASSET_DATA_BYTE_LENGTH)
+        )
diff --git a/python-packages/order_utils/test/test_doctest.py b/python-packages/order_utils/test/test_doctest.py
index a0e61f84a..ba5da5418 100644
--- a/python-packages/order_utils/test/test_doctest.py
+++ b/python-packages/order_utils/test/test_doctest.py
@@ -1,10 +1,24 @@
 """Exercise doctests for order_utils module."""
 
 from doctest import testmod
-from zero_ex.order_utils import signature_utils
 
+from zero_ex.dev_utils import abi_utils, type_assertions
+from zero_ex.order_utils import asset_data_utils
 
-def test_doctest():
-    """Invoke doctest on the module."""
-    (failure_count, _) = testmod(signature_utils)
+
+def test_doctest_asset_data_utils():
+    """Invoke doctest on the asset_data_utils module."""
+    (failure_count, _) = testmod(asset_data_utils)
+    assert failure_count == 0
+
+
+def test_doctest_abi_utils():
+    """Invoke doctest on the abi_utils module."""
+    (failure_count, _) = testmod(abi_utils)
+    assert failure_count == 0
+
+
+def test_doctest_type_assertions():
+    """Invoke doctest on the type_assertions module."""
+    (failure_count, _) = testmod(type_assertions)
     assert failure_count == 0
diff --git a/python-packages/order_utils/test/test_signature_utils.py b/python-packages/order_utils/test/test_signature_utils.py
deleted file mode 100644
index 7e830f9f8..000000000
--- a/python-packages/order_utils/test/test_signature_utils.py
+++ /dev/null
@@ -1,8 +0,0 @@
-"""Tests of 0x.order_utils.signature_utils.*."""
-
-from zero_ex.order_utils.signature_utils import ec_sign_order_hash
-
-
-def test_ec_sign_order_hash():
-    """Test the signing of order hashes."""
-    assert ec_sign_order_hash() == "stub return value"