Merge branch 'development'

* development: (939 commits)
  Add asset-buyer to published packages section in README
  Publish
  Updated CHANGELOGS
  Update BuyQuote interface
  force re-build
  Add website build to instructions
  Revert format and re-add changes
  Build website in parallel with other tests since no other test relies on it being built to run
  Add back sourceMap support for both dev/prod
  Upgrade webpack
  Add missing default options
  Remove unused constants
  Add fee order with a takerFee
  Add additional order factory methods and refactor test to use them
  Add comments about buy quote calculation
  Update CHANGELOG
  Fix linter
  Add additional test for slippage
  Add buy_quote_calculator_test
  Add 0x Instant to bundle analysis
  ...

23 files changed, 864 insertions, 58 deletions

diff --git a/packages/contract-wrappers/src/artifacts.ts b/packages/contract-wrappers/src/artifacts.ts
index 2481b311a..925f34162 100644
--- a/packages/contract-wrappers/src/artifacts.ts
+++ b/packages/contract-wrappers/src/artifacts.ts
@@ -1,4 +1,4 @@
-import { ContractArtifact } from '@0xproject/sol-compiler';
+import { ContractArtifact } from 'ethereum-types';
 
 import * as DummyERC20Token from './artifacts/DummyERC20Token.json';
 import * as DummyERC721Token from './artifacts/DummyERC721Token.json';
@@ -8,6 +8,7 @@ import * as ERC721Proxy from './artifacts/ERC721Proxy.json';
 import * as ERC721Token from './artifacts/ERC721Token.json';
 import * as Exchange from './artifacts/Exchange.json';
 import * as Forwarder from './artifacts/Forwarder.json';
+import * as OrderValidator from './artifacts/OrderValidator.json';
 import * as EtherToken from './artifacts/WETH9.json';
 import * as ZRXToken from './artifacts/ZRXToken.json';
 
@@ -22,4 +23,5 @@ export const artifacts = {
     ERC20Proxy: (ERC20Proxy as any) as ContractArtifact,
     ERC721Proxy: (ERC721Proxy as any) as ContractArtifact,
     Forwarder: (Forwarder as any) as ContractArtifact,
+    OrderValidator: (OrderValidator as any) as ContractArtifact,
 };
diff --git a/packages/contract-wrappers/src/contract_wrappers.ts b/packages/contract-wrappers/src/contract_wrappers.ts
index 4277a0746..89402029b 100644
--- a/packages/contract-wrappers/src/contract_wrappers.ts
+++ b/packages/contract-wrappers/src/contract_wrappers.ts
@@ -12,6 +12,7 @@ import { ERC721TokenWrapper } from './contract_wrappers/erc721_token_wrapper';
 import { EtherTokenWrapper } from './contract_wrappers/ether_token_wrapper';
 import { ExchangeWrapper } from './contract_wrappers/exchange_wrapper';
 import { ForwarderWrapper } from './contract_wrappers/forwarder_wrapper';
+import { OrderValidatorWrapper } from './contract_wrappers/order_validator_wrapper';
 import { ContractWrappersConfigSchema } from './schemas/contract_wrappers_config_schema';
 import { contractWrappersPrivateNetworkConfigSchema } from './schemas/contract_wrappers_private_network_config_schema';
 import { contractWrappersPublicNetworkConfigSchema } from './schemas/contract_wrappers_public_network_config_schema';
@@ -52,8 +53,12 @@ export class ContractWrappers {
      * An instance of the ForwarderWrapper class containing methods for interacting with any Forwarder smart contract.
      */
     public forwarder: ForwarderWrapper;
+    /**
+     * An instance of the OrderValidatorWrapper class containing methods for interacting with any OrderValidator smart contract.
+     */
+    public orderValidator: OrderValidatorWrapper;
 
-    private _web3Wrapper: Web3Wrapper;
+    private readonly _web3Wrapper: Web3Wrapper;
     /**
      * Instantiates a new ContractWrappers instance.
      * @param   provider    The Provider instance you would like the 0x.js library to use for interacting with
@@ -106,6 +111,8 @@ export class ContractWrappers {
         this.exchange = new ExchangeWrapper(
             this._web3Wrapper,
             config.networkId,
+            this.erc20Token,
+            this.erc721Token,
             config.exchangeContractAddress,
             config.zrxContractAddress,
             blockPollingIntervalMs,
@@ -116,6 +123,7 @@ export class ContractWrappers {
             config.forwarderContractAddress,
             config.zrxContractAddress,
         );
+        this.orderValidator = new OrderValidatorWrapper(this._web3Wrapper, config.networkId);
     }
     /**
      * Sets a new web3 provider for 0x.js. Updating the provider will stop all
diff --git a/packages/contract-wrappers/src/contract_wrappers/contract_wrapper.ts b/packages/contract-wrappers/src/contract_wrappers/contract_wrapper.ts
index daf70253a..f7a89e3be 100644
--- a/packages/contract-wrappers/src/contract_wrappers/contract_wrapper.ts
+++ b/packages/contract-wrappers/src/contract_wrappers/contract_wrapper.ts
@@ -1,7 +1,15 @@
-import { ContractArtifact } from '@0xproject/sol-compiler';
 import { AbiDecoder, intervalUtils, logUtils } from '@0xproject/utils';
-import { Web3Wrapper } from '@0xproject/web3-wrapper';
-import { BlockParamLiteral, ContractAbi, FilterObject, LogEntry, LogWithDecodedArgs, RawLog } from 'ethereum-types';
+import { marshaller, Web3Wrapper } from '@0xproject/web3-wrapper';
+import {
+    BlockParamLiteral,
+    ContractAbi,
+    ContractArtifact,
+    FilterObject,
+    LogEntry,
+    LogWithDecodedArgs,
+    RawLog,
+    RawLogEntry,
+} from 'ethereum-types';
 import { Block, BlockAndLogStreamer, Log } from 'ethereumjs-blockstream';
 import * as _ from 'lodash';
 
@@ -138,16 +146,20 @@ export abstract class ContractWrapper {
     }
     protected _getContractAddress(artifact: ContractArtifact, addressIfExists?: string): string {
         if (_.isUndefined(addressIfExists)) {
+            if (_.isUndefined(artifact.networks[this._networkId])) {
+                throw new Error(ContractWrappersError.ContractNotDeployedOnNetwork);
+            }
             const contractAddress = artifact.networks[this._networkId].address;
             if (_.isUndefined(contractAddress)) {
-                throw new Error(ContractWrappersError.ExchangeContractDoesNotExist);
+                throw new Error(CONTRACT_NAME_TO_NOT_FOUND_ERROR[artifact.contractName]);
             }
             return contractAddress;
         } else {
             return addressIfExists;
         }
     }
-    private _onLogStateChanged<ArgsType extends ContractEventArgs>(isRemoved: boolean, log: LogEntry): void {
+    private _onLogStateChanged<ArgsType extends ContractEventArgs>(isRemoved: boolean, rawLog: RawLogEntry): void {
+        const log: LogEntry = marshaller.unmarshalLog(rawLog);
         _.forEach(this._filters, (filter: FilterObject, filterToken: string) => {
             if (filterUtils.matchesFilter(log, filter)) {
                 const decodedLog = this._tryToDecodeLogOrNoop(log) as LogWithDecodedArgs<ArgsType>;
@@ -164,8 +176,8 @@ export abstract class ContractWrapper {
             throw new Error(ContractWrappersError.SubscriptionAlreadyPresent);
         }
         this._blockAndLogStreamerIfExists = new BlockAndLogStreamer(
-            this._web3Wrapper.getBlockAsync.bind(this._web3Wrapper),
-            this._web3Wrapper.getLogsAsync.bind(this._web3Wrapper),
+            this._blockstreamGetBlockOrNullAsync.bind(this),
+            this._blockstreamGetLogsAsync.bind(this),
             ContractWrapper._onBlockAndLogStreamerError.bind(this, isVerbose),
         );
         const catchAllLogFilter = {};
@@ -184,6 +196,32 @@ export abstract class ContractWrapper {
             this._onLogStateChanged.bind(this, isRemoved),
         );
     }
+    // This method only exists in order to comply with the expected interface of Blockstream's constructor
+    private async _blockstreamGetBlockOrNullAsync(hash: string): Promise<Block | null> {
+        const shouldIncludeTransactionData = false;
+        const blockOrNull = await this._web3Wrapper.sendRawPayloadAsync<Block | null>({
+            method: 'eth_getBlockByHash',
+            params: [hash, shouldIncludeTransactionData],
+        });
+        return blockOrNull;
+    }
+    // This method only exists in order to comply with the expected interface of Blockstream's constructor
+    private async _blockstreamGetLatestBlockOrNullAsync(): Promise<Block | null> {
+        const shouldIncludeTransactionData = false;
+        const blockOrNull = await this._web3Wrapper.sendRawPayloadAsync<Block | null>({
+            method: 'eth_getBlockByNumber',
+            params: [BlockParamLiteral.Latest, shouldIncludeTransactionData],
+        });
+        return blockOrNull;
+    }
+    // This method only exists in order to comply with the expected interface of Blockstream's constructor
+    private async _blockstreamGetLogsAsync(filterOptions: FilterObject): Promise<RawLogEntry[]> {
+        const logs = await this._web3Wrapper.sendRawPayloadAsync<RawLogEntry[]>({
+            method: 'eth_getLogs',
+            params: [filterOptions],
+        });
+        return logs as RawLogEntry[];
+    }
     // HACK: This should be a package-scoped method (which doesn't exist in TS)
     // We don't want this method available in the public interface for all classes
     // who inherit from ContractWrapper, and it is only used by the internal implementation
@@ -202,11 +240,14 @@ export abstract class ContractWrapper {
         delete this._blockAndLogStreamerIfExists;
     }
     private async _reconcileBlockAsync(): Promise<void> {
-        const latestBlock = await this._web3Wrapper.getBlockAsync(BlockParamLiteral.Latest);
+        const latestBlockOrNull = await this._blockstreamGetLatestBlockOrNullAsync();
+        if (_.isNull(latestBlockOrNull)) {
+            return; // noop
+        }
         // We need to coerce to Block type cause Web3.Block includes types for mempool blocks
         if (!_.isUndefined(this._blockAndLogStreamerIfExists)) {
             // If we clear the interval while fetching the block - this._blockAndLogStreamer will be undefined
-            await this._blockAndLogStreamerIfExists.reconcileNewBlock((latestBlock as any) as Block);
+            await this._blockAndLogStreamerIfExists.reconcileNewBlock(latestBlockOrNull);
         }
     }
 }
diff --git a/packages/contract-wrappers/src/contract_wrappers/erc20_proxy_wrapper.ts b/packages/contract-wrappers/src/contract_wrappers/erc20_proxy_wrapper.ts
index 821d1a8a2..ff027d78a 100644
--- a/packages/contract-wrappers/src/contract_wrappers/erc20_proxy_wrapper.ts
+++ b/packages/contract-wrappers/src/contract_wrappers/erc20_proxy_wrapper.ts
@@ -16,6 +16,13 @@ export class ERC20ProxyWrapper extends ContractWrapper {
     public abi: ContractAbi = artifacts.ERC20Proxy.compilerOutput.abi;
     private _erc20ProxyContractIfExists?: ERC20ProxyContract;
     private _contractAddressIfExists?: string;
+    /**
+     * Instantiate ERC20ProxyWrapper
+     * @param web3Wrapper Web3Wrapper instance to use
+     * @param networkId Desired networkId
+     * @param contractAddressIfExists The contract address to use. This is usually pulled from
+     * the artifacts but needs to be specified when using with your own custom testnet.
+     */
     constructor(web3Wrapper: Web3Wrapper, networkId: number, contractAddressIfExists?: string) {
         super(web3Wrapper, networkId);
         this._contractAddressIfExists = contractAddressIfExists;
diff --git a/packages/contract-wrappers/src/contract_wrappers/erc20_token_wrapper.ts b/packages/contract-wrappers/src/contract_wrappers/erc20_token_wrapper.ts
index 17bda5085..4625cef6a 100644
--- a/packages/contract-wrappers/src/contract_wrappers/erc20_token_wrapper.ts
+++ b/packages/contract-wrappers/src/contract_wrappers/erc20_token_wrapper.ts
@@ -34,6 +34,13 @@ export class ERC20TokenWrapper extends ContractWrapper {
     public UNLIMITED_ALLOWANCE_IN_BASE_UNITS = constants.UNLIMITED_ALLOWANCE_IN_BASE_UNITS;
     private _tokenContractsByAddress: { [address: string]: ERC20TokenContract };
     private _erc20ProxyWrapper: ERC20ProxyWrapper;
+    /**
+     * Instantiate ERC20TokenWrapper
+     * @param web3Wrapper Web3Wrapper instance to use
+     * @param networkId Desired networkId
+     * @param erc20ProxyWrapper The ERC20ProxyWrapper instance to use
+     * @param blockPollingIntervalMs The block polling interval to use for active subscriptions
+     */
     constructor(
         web3Wrapper: Web3Wrapper,
         networkId: number,
diff --git a/packages/contract-wrappers/src/contract_wrappers/erc721_proxy_wrapper.ts b/packages/contract-wrappers/src/contract_wrappers/erc721_proxy_wrapper.ts
index 38ecd4687..933c1dc27 100644
--- a/packages/contract-wrappers/src/contract_wrappers/erc721_proxy_wrapper.ts
+++ b/packages/contract-wrappers/src/contract_wrappers/erc721_proxy_wrapper.ts
@@ -16,6 +16,13 @@ export class ERC721ProxyWrapper extends ContractWrapper {
     public abi: ContractAbi = artifacts.ERC20Proxy.compilerOutput.abi;
     private _erc721ProxyContractIfExists?: ERC721ProxyContract;
     private _contractAddressIfExists?: string;
+    /**
+     * Instantiate ERC721ProxyWrapper
+     * @param web3Wrapper Web3Wrapper instance to use
+     * @param networkId Desired networkId
+     * @param contractAddressIfExists The contract address to use. This is usually pulled from
+     * the artifacts but needs to be specified when using with your own custom testnet.
+     */
     constructor(web3Wrapper: Web3Wrapper, networkId: number, contractAddressIfExists?: string) {
         super(web3Wrapper, networkId);
         this._contractAddressIfExists = contractAddressIfExists;
diff --git a/packages/contract-wrappers/src/contract_wrappers/erc721_token_wrapper.ts b/packages/contract-wrappers/src/contract_wrappers/erc721_token_wrapper.ts
index 7231e0bde..590dbbf74 100644
--- a/packages/contract-wrappers/src/contract_wrappers/erc721_token_wrapper.ts
+++ b/packages/contract-wrappers/src/contract_wrappers/erc721_token_wrapper.ts
@@ -33,6 +33,13 @@ export class ERC721TokenWrapper extends ContractWrapper {
     public abi: ContractAbi = artifacts.ERC721Token.compilerOutput.abi;
     private _tokenContractsByAddress: { [address: string]: ERC721TokenContract };
     private _erc721ProxyWrapper: ERC721ProxyWrapper;
+    /**
+     * Instantiate ERC721TokenWrapper
+     * @param web3Wrapper Web3Wrapper instance to use
+     * @param networkId Desired networkId
+     * @param erc721ProxyWrapper The ERC721ProxyWrapper instance to use
+     * @param blockPollingIntervalMs The block polling interval to use for active subscriptions
+     */
     constructor(
         web3Wrapper: Web3Wrapper,
         networkId: number,
diff --git a/packages/contract-wrappers/src/contract_wrappers/ether_token_wrapper.ts b/packages/contract-wrappers/src/contract_wrappers/ether_token_wrapper.ts
index 5046d3667..1ac01812e 100644
--- a/packages/contract-wrappers/src/contract_wrappers/ether_token_wrapper.ts
+++ b/packages/contract-wrappers/src/contract_wrappers/ether_token_wrapper.ts
@@ -24,6 +24,13 @@ export class EtherTokenWrapper extends ContractWrapper {
         [address: string]: WETH9Contract;
     } = {};
     private _erc20TokenWrapper: ERC20TokenWrapper;
+    /**
+     * Instantiate EtherTokenWrapper.
+     * @param web3Wrapper Web3Wrapper instance to use
+     * @param networkId Desired networkId
+     * @param erc20TokenWrapper The ERC20TokenWrapper instance to use
+     * @param blockPollingIntervalMs The block polling interval to use for active subscriptions
+     */
     constructor(
         web3Wrapper: Web3Wrapper,
         networkId: number,
diff --git a/packages/contract-wrappers/src/contract_wrappers/exchange_wrapper.ts b/packages/contract-wrappers/src/contract_wrappers/exchange_wrapper.ts
index 48bd00f90..dc9ffcbf7 100644
--- a/packages/contract-wrappers/src/contract_wrappers/exchange_wrapper.ts
+++ b/packages/contract-wrappers/src/contract_wrappers/exchange_wrapper.ts
@@ -1,12 +1,19 @@
 import { schemas } from '@0xproject/json-schemas';
-import { assetDataUtils } from '@0xproject/order-utils';
+import {
+    assetDataUtils,
+    BalanceAndProxyAllowanceLazyStore,
+    ExchangeTransferSimulator,
+    OrderValidationUtils,
+} from '@0xproject/order-utils';
 import { AssetProxyId, Order, SignedOrder } from '@0xproject/types';
 import { BigNumber } from '@0xproject/utils';
 import { Web3Wrapper } from '@0xproject/web3-wrapper';
-import { ContractAbi, LogWithDecodedArgs } from 'ethereum-types';
+import { BlockParamLiteral, ContractAbi, LogWithDecodedArgs } from 'ethereum-types';
 import * as _ from 'lodash';
 
 import { artifacts } from '../artifacts';
+import { AssetBalanceAndProxyAllowanceFetcher } from '../fetchers/asset_balance_and_proxy_allowance_fetcher';
+import { OrderFilledCancelledFetcher } from '../fetchers/order_filled_cancelled_fetcher';
 import { methodOptsSchema } from '../schemas/method_opts_schema';
 import { orderTxOptsSchema } from '../schemas/order_tx_opts_schema';
 import { txOptsSchema } from '../schemas/tx_opts_schema';
@@ -17,12 +24,17 @@ import {
     IndexedFilterValues,
     MethodOpts,
     OrderInfo,
+    OrderStatus,
     OrderTransactionOpts,
+    ValidateOrderFillableOpts,
 } from '../types';
 import { assert } from '../utils/assert';
 import { decorators } from '../utils/decorators';
+import { TransactionEncoder } from '../utils/transaction_encoder';
 
 import { ContractWrapper } from './contract_wrapper';
+import { ERC20TokenWrapper } from './erc20_token_wrapper';
+import { ERC721TokenWrapper } from './erc721_token_wrapper';
 import { ExchangeContract, ExchangeEventArgs, ExchangeEvents } from './generated/exchange';
 
 /**
@@ -32,16 +44,32 @@ import { ExchangeContract, ExchangeEventArgs, ExchangeEvents } from './generated
 export class ExchangeWrapper extends ContractWrapper {
     public abi: ContractAbi = artifacts.Exchange.compilerOutput.abi;
     private _exchangeContractIfExists?: ExchangeContract;
+    private _erc721TokenWrapper: ERC721TokenWrapper;
+    private _erc20TokenWrapper: ERC20TokenWrapper;
     private _contractAddressIfExists?: string;
     private _zrxContractAddressIfExists?: string;
+    /**
+     * Instantiate ExchangeWrapper
+     * @param web3Wrapper Web3Wrapper instance to use
+     * @param networkId Desired networkId
+     * @param contractAddressIfExists The exchange contract address to use. This is usually pulled from
+     * the artifacts but needs to be specified when using with your own custom testnet.
+     * @param zrxContractAddressIfExists The ZRXToken contract address to use. This is usually pulled from
+     * the artifacts but needs to be specified when using with your own custom testnet.
+     * @param blockPollingIntervalMs The block polling interval to use for active subscriptions
+     */
     constructor(
         web3Wrapper: Web3Wrapper,
         networkId: number,
+        erc20TokenWrapper: ERC20TokenWrapper,
+        erc721TokenWrapper: ERC721TokenWrapper,
         contractAddressIfExists?: string,
         zrxContractAddressIfExists?: string,
         blockPollingIntervalMs?: number,
     ) {
         super(web3Wrapper, networkId, blockPollingIntervalMs);
+        this._erc20TokenWrapper = erc20TokenWrapper;
+        this._erc721TokenWrapper = erc721TokenWrapper;
         this._contractAddressIfExists = contractAddressIfExists;
         this._zrxContractAddressIfExists = zrxContractAddressIfExists;
     }
@@ -665,6 +693,7 @@ export class ExchangeWrapper extends ContractWrapper {
      * @param leftSignedOrder  First order to match.
      * @param rightSignedOrder Second order to match.
      * @param takerAddress     The address that sends the transaction and gets the spread.
+     * @param orderTransactionOpts Optional arguments this method accepts.
      * @return Transaction hash.
      */
     @decorators.asyncZeroExErrorHandler
@@ -723,6 +752,7 @@ export class ExchangeWrapper extends ContractWrapper {
      * @param signerAddress Address that should have signed the given hash.
      * @param signature     Proof that the hash has been signed by signer.
      * @param senderAddress Address that should send the transaction.
+     * @param orderTransactionOpts Optional arguments this method accepts.
      * @returns Transaction hash.
      */
     @decorators.asyncZeroExErrorHandler
@@ -901,7 +931,7 @@ export class ExchangeWrapper extends ContractWrapper {
     /**
      * Cancel a given order.
      * @param   order           An object that conforms to the Order or SignedOrder interface. The order you would like to cancel.
-     * @param   transactionOpts Optional arguments this method accepts.
+     * @param   orderTransactionOpts Optional arguments this method accepts.
      * @return  Transaction hash.
      */
     @decorators.asyncZeroExErrorHandler
@@ -1072,6 +1102,64 @@ export class ExchangeWrapper extends ContractWrapper {
         return logs;
     }
     /**
+     * Validate if the supplied order is fillable, and throw if it isn't
+     * @param signedOrder SignedOrder of interest
+     * @param opts ValidateOrderFillableOpts options (e.g expectedFillTakerTokenAmount.
+     * If it isn't supplied, we check if the order is fillable for a non-zero amount)
+     */
+    public async validateOrderFillableOrThrowAsync(
+        signedOrder: SignedOrder,
+        opts: ValidateOrderFillableOpts = {},
+    ): Promise<void> {
+        const balanceAllowanceFetcher = new AssetBalanceAndProxyAllowanceFetcher(
+            this._erc20TokenWrapper,
+            this._erc721TokenWrapper,
+            BlockParamLiteral.Latest,
+        );
+        const balanceAllowanceStore = new BalanceAndProxyAllowanceLazyStore(balanceAllowanceFetcher);
+        const exchangeTradeSimulator = new ExchangeTransferSimulator(balanceAllowanceStore);
+
+        const expectedFillTakerTokenAmountIfExists = opts.expectedFillTakerTokenAmount;
+        const filledCancelledFetcher = new OrderFilledCancelledFetcher(this, BlockParamLiteral.Latest);
+        const orderValidationUtils = new OrderValidationUtils(filledCancelledFetcher);
+        await orderValidationUtils.validateOrderFillableOrThrowAsync(
+            exchangeTradeSimulator,
+            signedOrder,
+            this.getZRXAssetData(),
+            expectedFillTakerTokenAmountIfExists,
+        );
+    }
+    /**
+     * Validate a call to FillOrder and throw if it wouldn't succeed
+     * @param signedOrder SignedOrder of interest
+     * @param fillTakerAssetAmount Amount we'd like to fill the order for
+     * @param takerAddress The taker of the order
+     */
+    public async validateFillOrderThrowIfInvalidAsync(
+        signedOrder: SignedOrder,
+        fillTakerAssetAmount: BigNumber,
+        takerAddress: string,
+    ): Promise<void> {
+        const balanceAllowanceFetcher = new AssetBalanceAndProxyAllowanceFetcher(
+            this._erc20TokenWrapper,
+            this._erc721TokenWrapper,
+            BlockParamLiteral.Latest,
+        );
+        const balanceAllowanceStore = new BalanceAndProxyAllowanceLazyStore(balanceAllowanceFetcher);
+        const exchangeTradeSimulator = new ExchangeTransferSimulator(balanceAllowanceStore);
+
+        const filledCancelledFetcher = new OrderFilledCancelledFetcher(this, BlockParamLiteral.Latest);
+        const orderValidationUtils = new OrderValidationUtils(filledCancelledFetcher);
+        await orderValidationUtils.validateFillOrderThrowIfInvalidAsync(
+            exchangeTradeSimulator,
+            this._web3Wrapper.getProvider(),
+            signedOrder,
+            fillTakerAssetAmount,
+            takerAddress,
+            this.getZRXAssetData(),
+        );
+    }
+    /**
      * Retrieves the Ethereum address of the Exchange contract deployed on the network
      * that the user-passed web3 provider is connected to.
      * @returns The Ethereum address of the Exchange contract being used.
@@ -1097,6 +1185,16 @@ export class ExchangeWrapper extends ContractWrapper {
         const zrxAssetData = assetDataUtils.encodeERC20AssetData(zrxTokenAddress);
         return zrxAssetData;
     }
+    /**
+     * Returns a Transaction Encoder. Transaction messages exist for the purpose of calling methods on the Exchange contract
+     * in the context of another address.
+     * @return TransactionEncoder
+     */
+    public async transactionEncoderAsync(): Promise<TransactionEncoder> {
+        const exchangeInstance = await this._getExchangeContractAsync();
+        const encoder = new TransactionEncoder(exchangeInstance);
+        return encoder;
+    }
     // tslint:disable:no-unused-variable
     private _invalidateContractInstances(): void {
         this.unsubscribeAll();
diff --git a/packages/contract-wrappers/src/contract_wrappers/forwarder_wrapper.ts b/packages/contract-wrappers/src/contract_wrappers/forwarder_wrapper.ts
index 13ef0fe01..906222731 100644
--- a/packages/contract-wrappers/src/contract_wrappers/forwarder_wrapper.ts
+++ b/packages/contract-wrappers/src/contract_wrappers/forwarder_wrapper.ts
@@ -12,6 +12,7 @@ import { TransactionOpts } from '../types';
 import { assert } from '../utils/assert';
 import { calldataOptimizationUtils } from '../utils/calldata_optimization_utils';
 import { constants } from '../utils/constants';
+import { utils } from '../utils/utils';
 
 import { ContractWrapper } from './contract_wrapper';
 import { ForwarderContract } from './generated/forwarder';
@@ -57,7 +58,7 @@ export class ForwarderWrapper extends ContractWrapper {
         takerAddress: string,
         ethAmount: BigNumber,
         signedFeeOrders: SignedOrder[] = [],
-        feePercentage: BigNumber = constants.ZERO_AMOUNT,
+        feePercentage: number = 0,
         feeRecipientAddress: string = constants.NULL_ADDRESS,
         txOpts: TransactionOpts = {},
     ): Promise<string> {
@@ -66,7 +67,7 @@ export class ForwarderWrapper extends ContractWrapper {
         await assert.isSenderAddressAsync('takerAddress', takerAddress, this._web3Wrapper);
         assert.isBigNumber('ethAmount', ethAmount);
         assert.doesConformToSchema('signedFeeOrders', signedFeeOrders, schemas.signedOrdersSchema);
-        assert.isBigNumber('feePercentage', feePercentage);
+        assert.isNumber('feePercentage', feePercentage);
         assert.isETHAddressHex('feeRecipientAddress', feeRecipientAddress);
         assert.doesConformToSchema('txOpts', txOpts, txOptsSchema);
         // other assertions
@@ -76,6 +77,8 @@ export class ForwarderWrapper extends ContractWrapper {
             this.getZRXTokenAddress(),
             this.getEtherTokenAddress(),
         );
+        // format feePercentage
+        const formattedFeePercentage = utils.numberPercentageToEtherTokenAmountPercentage(feePercentage);
         // lowercase input addresses
         const normalizedTakerAddress = takerAddress.toLowerCase();
         const normalizedFeeRecipientAddress = feeRecipientAddress.toLowerCase();
@@ -89,7 +92,7 @@ export class ForwarderWrapper extends ContractWrapper {
             _.map(optimizedMarketOrders, order => order.signature),
             optimizedFeeOrders,
             _.map(optimizedFeeOrders, order => order.signature),
-            feePercentage,
+            formattedFeePercentage,
             feeRecipientAddress,
             {
                 value: ethAmount,
@@ -124,7 +127,7 @@ export class ForwarderWrapper extends ContractWrapper {
         takerAddress: string,
         ethAmount: BigNumber,
         signedFeeOrders: SignedOrder[] = [],
-        feePercentage: BigNumber = constants.ZERO_AMOUNT,
+        feePercentage: number = 0,
         feeRecipientAddress: string = constants.NULL_ADDRESS,
         txOpts: TransactionOpts = {},
     ): Promise<string> {
@@ -134,7 +137,7 @@ export class ForwarderWrapper extends ContractWrapper {
         await assert.isSenderAddressAsync('takerAddress', takerAddress, this._web3Wrapper);
         assert.isBigNumber('ethAmount', ethAmount);
         assert.doesConformToSchema('signedFeeOrders', signedFeeOrders, schemas.signedOrdersSchema);
-        assert.isBigNumber('feePercentage', feePercentage);
+        assert.isNumber('feePercentage', feePercentage);
         assert.isETHAddressHex('feeRecipientAddress', feeRecipientAddress);
         assert.doesConformToSchema('txOpts', txOpts, txOptsSchema);
         // other assertions
@@ -144,6 +147,8 @@ export class ForwarderWrapper extends ContractWrapper {
             this.getZRXTokenAddress(),
             this.getEtherTokenAddress(),
         );
+        // format feePercentage
+        const formattedFeePercentage = utils.numberPercentageToEtherTokenAmountPercentage(feePercentage);
         // lowercase input addresses
         const normalizedTakerAddress = takerAddress.toLowerCase();
         const normalizedFeeRecipientAddress = feeRecipientAddress.toLowerCase();
@@ -158,7 +163,7 @@ export class ForwarderWrapper extends ContractWrapper {
             _.map(optimizedMarketOrders, order => order.signature),
             optimizedFeeOrders,
             _.map(optimizedFeeOrders, order => order.signature),
-            feePercentage,
+            formattedFeePercentage,
             feeRecipientAddress,
             {
                 value: ethAmount,
diff --git a/packages/contract-wrappers/src/contract_wrappers/order_validator_wrapper.ts b/packages/contract-wrappers/src/contract_wrappers/order_validator_wrapper.ts
new file mode 100644
index 000000000..1da88f624
--- /dev/null
+++ b/packages/contract-wrappers/src/contract_wrappers/order_validator_wrapper.ts
@@ -0,0 +1,187 @@
+import { schemas } from '@0xproject/json-schemas';
+import { SignedOrder } from '@0xproject/types';
+import { BigNumber } from '@0xproject/utils';
+import { Web3Wrapper } from '@0xproject/web3-wrapper';
+import { ContractAbi } from 'ethereum-types';
+import * as _ from 'lodash';
+
+import { artifacts } from '../artifacts';
+import { BalanceAndAllowance, OrderAndTraderInfo, TraderInfo } from '../types';
+import { assert } from '../utils/assert';
+
+import { ContractWrapper } from './contract_wrapper';
+import { OrderValidatorContract } from './generated/order_validator';
+
+/**
+ * This class includes the functionality related to interacting with the OrderValidator contract.
+ */
+export class OrderValidatorWrapper extends ContractWrapper {
+    public abi: ContractAbi = artifacts.OrderValidator.compilerOutput.abi;
+    private _orderValidatorContractIfExists?: OrderValidatorContract;
+    /**
+     * Instantiate OrderValidatorWrapper
+     * @param web3Wrapper Web3Wrapper instance to use
+     * @param networkId Desired networkId
+     */
+    constructor(web3Wrapper: Web3Wrapper, networkId: number) {
+        super(web3Wrapper, networkId);
+    }
+    /**
+     * Get an object conforming to OrderAndTraderInfo containing on-chain information of the provided order and address
+     * @param   order           An object conforming to SignedOrder
+     * @param   takerAddress    An ethereum address
+     * @return  OrderAndTraderInfo
+     */
+    public async getOrderAndTraderInfoAsync(order: SignedOrder, takerAddress: string): Promise<OrderAndTraderInfo> {
+        assert.doesConformToSchema('order', order, schemas.signedOrderSchema);
+        assert.isETHAddressHex('takerAddress', takerAddress);
+        const OrderValidatorContractInstance = await this._getOrderValidatorContractAsync();
+        const orderAndTraderInfo = await OrderValidatorContractInstance.getOrderAndTraderInfo.callAsync(
+            order,
+            takerAddress,
+        );
+        const result = {
+            orderInfo: orderAndTraderInfo[0],
+            traderInfo: orderAndTraderInfo[1],
+        };
+        return result;
+    }
+    /**
+     * Get an array of objects conforming to OrderAndTraderInfo containing on-chain information of the provided orders and addresses
+     * @param   orders          An array of objects conforming to SignedOrder
+     * @param   takerAddresses  An array of ethereum addresses
+     * @return  array of OrderAndTraderInfo
+     */
+    public async getOrdersAndTradersInfoAsync(
+        orders: SignedOrder[],
+        takerAddresses: string[],
+    ): Promise<OrderAndTraderInfo[]> {
+        assert.doesConformToSchema('orders', orders, schemas.signedOrdersSchema);
+        _.forEach(takerAddresses, (takerAddress, index) =>
+            assert.isETHAddressHex(`takerAddresses[${index}]`, takerAddress),
+        );
+        assert.assert(orders.length === takerAddresses.length, 'Expected orders.length to equal takerAddresses.length');
+        const OrderValidatorContractInstance = await this._getOrderValidatorContractAsync();
+        const ordersAndTradersInfo = await OrderValidatorContractInstance.getOrdersAndTradersInfo.callAsync(
+            orders,
+            takerAddresses,
+        );
+        const orderInfos = ordersAndTradersInfo[0];
+        const traderInfos = ordersAndTradersInfo[1];
+        const result = _.map(orderInfos, (orderInfo, index) => {
+            const traderInfo = traderInfos[index];
+            return {
+                orderInfo,
+                traderInfo,
+            };
+        });
+        return result;
+    }
+    /**
+     * Get an object conforming to TraderInfo containing on-chain balance and allowances for maker and taker of order
+     * @param   order           An object conforming to SignedOrder
+     * @param   takerAddress    An ethereum address
+     * @return  TraderInfo
+     */
+    public async getTraderInfoAsync(order: SignedOrder, takerAddress: string): Promise<TraderInfo> {
+        assert.doesConformToSchema('order', order, schemas.signedOrderSchema);
+        assert.isETHAddressHex('takerAddress', takerAddress);
+        const OrderValidatorContractInstance = await this._getOrderValidatorContractAsync();
+        const result = await OrderValidatorContractInstance.getTraderInfo.callAsync(order, takerAddress);
+        return result;
+    }
+    /**
+     * Get an array of objects conforming to TraderInfo containing on-chain balance and allowances for maker and taker of order
+     * @param   orders          An array of objects conforming to SignedOrder
+     * @param   takerAddresses  An array of ethereum addresses
+     * @return  array of TraderInfo
+     */
+    public async getTradersInfoAsync(orders: SignedOrder[], takerAddresses: string[]): Promise<TraderInfo[]> {
+        assert.doesConformToSchema('orders', orders, schemas.signedOrdersSchema);
+        _.forEach(takerAddresses, (takerAddress, index) =>
+            assert.isETHAddressHex(`takerAddresses[${index}]`, takerAddress),
+        );
+        assert.assert(orders.length === takerAddresses.length, 'Expected orders.length to equal takerAddresses.length');
+        const OrderValidatorContractInstance = await this._getOrderValidatorContractAsync();
+        const result = await OrderValidatorContractInstance.getTradersInfo.callAsync(orders, takerAddresses);
+        return result;
+    }
+    /**
+     * Get an object conforming to BalanceAndAllowance containing on-chain balance and allowance for some address and assetData
+     * @param   address     An ethereum address
+     * @param   assetData   An encoded string that can be decoded by a specified proxy contract
+     * @return  BalanceAndAllowance
+     */
+    public async getBalanceAndAllowanceAsync(address: string, assetData: string): Promise<BalanceAndAllowance> {
+        assert.isETHAddressHex('address', address);
+        assert.isHexString('assetData', assetData);
+        const OrderValidatorContractInstance = await this._getOrderValidatorContractAsync();
+        const balanceAndAllowance = await OrderValidatorContractInstance.getBalanceAndAllowance.callAsync(
+            address,
+            assetData,
+        );
+        const result = {
+            balance: balanceAndAllowance[0],
+            allowance: balanceAndAllowance[1],
+        };
+        return result;
+    }
+    /**
+     * Get an array of objects conforming to BalanceAndAllowance containing on-chain balance and allowance for some address and array of assetDatas
+     * @param   address     An ethereum address
+     * @param   assetDatas  An array of encoded strings that can be decoded by a specified proxy contract
+     * @return  BalanceAndAllowance
+     */
+    public async getBalancesAndAllowancesAsync(address: string, assetDatas: string[]): Promise<BalanceAndAllowance[]> {
+        assert.isETHAddressHex('address', address);
+        _.forEach(assetDatas, (assetData, index) => assert.isHexString(`assetDatas[${index}]`, assetData));
+        const OrderValidatorContractInstance = await this._getOrderValidatorContractAsync();
+        const balancesAndAllowances = await OrderValidatorContractInstance.getBalancesAndAllowances.callAsync(
+            address,
+            assetDatas,
+        );
+        const balances = balancesAndAllowances[0];
+        const allowances = balancesAndAllowances[1];
+        const result = _.map(balances, (balance, index) => {
+            const allowance = allowances[index];
+            return {
+                balance,
+                allowance,
+            };
+        });
+        return result;
+    }
+    /**
+     * Get owner address of tokenId by calling `token.ownerOf(tokenId)`, but returns a null owner instead of reverting on an unowned token.
+     * @param   tokenAddress    An ethereum address
+     * @param   tokenId         An ERC721 tokenId
+     * @return  Owner of tokenId or null address if unowned
+     */
+    public async getERC721TokenOwnerAsync(tokenAddress: string, tokenId: BigNumber): Promise<string | undefined> {
+        assert.isETHAddressHex('tokenAddress', tokenAddress);
+        assert.isBigNumber('tokenId', tokenId);
+        const OrderValidatorContractInstance = await this._getOrderValidatorContractAsync();
+        const result = await OrderValidatorContractInstance.getERC721TokenOwner.callAsync(tokenAddress, tokenId);
+        return result;
+    }
+    // HACK: We don't want this method to be visible to the other units within that package but not to the end user.
+    // TS doesn't give that possibility and therefore we make it private and access it over an any cast. Because of that tslint sees it as unused.
+    // tslint:disable-next-line:no-unused-variable
+    private _invalidateContractInstance(): void {
+        delete this._orderValidatorContractIfExists;
+    }
+    private async _getOrderValidatorContractAsync(): Promise<OrderValidatorContract> {
+        if (!_.isUndefined(this._orderValidatorContractIfExists)) {
+            return this._orderValidatorContractIfExists;
+        }
+        const [abi, address] = await this._getContractAbiAndAddressFromArtifactsAsync(artifacts.OrderValidator);
+        const contractInstance = new OrderValidatorContract(
+            abi,
+            address,
+            this._web3Wrapper.getProvider(),
+            this._web3Wrapper.getContractDefaults(),
+        );
+        this._orderValidatorContractIfExists = contractInstance;
+        return this._orderValidatorContractIfExists;
+    }
+}
diff --git a/packages/contract-wrappers/src/fetchers/asset_balance_and_proxy_allowance_fetcher.ts b/packages/contract-wrappers/src/fetchers/asset_balance_and_proxy_allowance_fetcher.ts
new file mode 100644
index 000000000..023cd5ac3
--- /dev/null
+++ b/packages/contract-wrappers/src/fetchers/asset_balance_and_proxy_allowance_fetcher.ts
@@ -0,0 +1,77 @@
+// tslint:disable:no-unnecessary-type-assertion
+import { AbstractBalanceAndProxyAllowanceFetcher, assetDataUtils } from '@0xproject/order-utils';
+import { AssetProxyId, ERC20AssetData, ERC721AssetData } from '@0xproject/types';
+import { BigNumber } from '@0xproject/utils';
+import { BlockParamLiteral } from 'ethereum-types';
+
+import { ERC20TokenWrapper } from '../contract_wrappers/erc20_token_wrapper';
+import { ERC721TokenWrapper } from '../contract_wrappers/erc721_token_wrapper';
+
+export class AssetBalanceAndProxyAllowanceFetcher implements AbstractBalanceAndProxyAllowanceFetcher {
+    private readonly _erc20Token: ERC20TokenWrapper;
+    private readonly _erc721Token: ERC721TokenWrapper;
+    private readonly _stateLayer: BlockParamLiteral;
+    constructor(erc20Token: ERC20TokenWrapper, erc721Token: ERC721TokenWrapper, stateLayer: BlockParamLiteral) {
+        this._erc20Token = erc20Token;
+        this._erc721Token = erc721Token;
+        this._stateLayer = stateLayer;
+    }
+    public async getBalanceAsync(assetData: string, userAddress: string): Promise<BigNumber> {
+        const decodedAssetData = assetDataUtils.decodeAssetDataOrThrow(assetData);
+        if (decodedAssetData.assetProxyId === AssetProxyId.ERC20) {
+            const decodedERC20AssetData = decodedAssetData as ERC20AssetData;
+            const balance = await this._erc20Token.getBalanceAsync(decodedERC20AssetData.tokenAddress, userAddress, {
+                defaultBlock: this._stateLayer,
+            });
+            return balance;
+        } else {
+            const decodedERC721AssetData = decodedAssetData as ERC721AssetData;
+            const tokenOwner = await this._erc721Token.getOwnerOfAsync(
+                decodedERC721AssetData.tokenAddress,
+                decodedERC721AssetData.tokenId,
+                {
+                    defaultBlock: this._stateLayer,
+                },
+            );
+            const balance = tokenOwner === userAddress ? new BigNumber(1) : new BigNumber(0);
+            return balance;
+        }
+    }
+    public async getProxyAllowanceAsync(assetData: string, userAddress: string): Promise<BigNumber> {
+        const decodedAssetData = assetDataUtils.decodeAssetDataOrThrow(assetData);
+        if (decodedAssetData.assetProxyId === AssetProxyId.ERC20) {
+            const decodedERC20AssetData = decodedAssetData as ERC20AssetData;
+            const proxyAllowance = await this._erc20Token.getProxyAllowanceAsync(
+                decodedERC20AssetData.tokenAddress,
+                userAddress,
+                {
+                    defaultBlock: this._stateLayer,
+                },
+            );
+            return proxyAllowance;
+        } else {
+            const decodedERC721AssetData = decodedAssetData as ERC721AssetData;
+
+            const isApprovedForAll = await this._erc721Token.isProxyApprovedForAllAsync(
+                decodedERC721AssetData.tokenAddress,
+                userAddress,
+                {
+                    defaultBlock: this._stateLayer,
+                },
+            );
+            if (isApprovedForAll) {
+                return new BigNumber(this._erc20Token.UNLIMITED_ALLOWANCE_IN_BASE_UNITS);
+            } else {
+                const isApproved = await this._erc721Token.isProxyApprovedAsync(
+                    decodedERC721AssetData.tokenAddress,
+                    decodedERC721AssetData.tokenId,
+                    {
+                        defaultBlock: this._stateLayer,
+                    },
+                );
+                const proxyAllowance = isApproved ? new BigNumber(1) : new BigNumber(0);
+                return proxyAllowance;
+            }
+        }
+    }
+}
diff --git a/packages/contract-wrappers/src/fetchers/order_filled_cancelled_fetcher.ts b/packages/contract-wrappers/src/fetchers/order_filled_cancelled_fetcher.ts
new file mode 100644
index 000000000..7a252aed3
--- /dev/null
+++ b/packages/contract-wrappers/src/fetchers/order_filled_cancelled_fetcher.ts
@@ -0,0 +1,29 @@
+// tslint:disable:no-unnecessary-type-assertion
+import { AbstractOrderFilledCancelledFetcher } from '@0xproject/order-utils';
+import { BigNumber } from '@0xproject/utils';
+import { BlockParamLiteral } from 'ethereum-types';
+
+import { ExchangeWrapper } from '../contract_wrappers/exchange_wrapper';
+
+export class OrderFilledCancelledFetcher implements AbstractOrderFilledCancelledFetcher {
+    private readonly _exchange: ExchangeWrapper;
+    private readonly _stateLayer: BlockParamLiteral;
+    constructor(exchange: ExchangeWrapper, stateLayer: BlockParamLiteral) {
+        this._exchange = exchange;
+        this._stateLayer = stateLayer;
+    }
+    public async getFilledTakerAmountAsync(orderHash: string): Promise<BigNumber> {
+        const filledTakerAmount = this._exchange.getFilledTakerAssetAmountAsync(orderHash, {
+            defaultBlock: this._stateLayer,
+        });
+        return filledTakerAmount;
+    }
+    public async isOrderCancelledAsync(orderHash: string): Promise<boolean> {
+        const isCancelled = await this._exchange.isCancelledAsync(orderHash);
+        return isCancelled;
+    }
+    public getZRXAssetData(): string {
+        const zrxAssetData = this._exchange.getZRXAssetData();
+        return zrxAssetData;
+    }
+}
diff --git a/packages/contract-wrappers/src/index.ts b/packages/contract-wrappers/src/index.ts
index 1986e0004..2fcdd2ddb 100644
--- a/packages/contract-wrappers/src/index.ts
+++ b/packages/contract-wrappers/src/index.ts
@@ -6,46 +6,51 @@ export { ExchangeWrapper } from './contract_wrappers/exchange_wrapper';
 export { ERC20ProxyWrapper } from './contract_wrappers/erc20_proxy_wrapper';
 export { ERC721ProxyWrapper } from './contract_wrappers/erc721_proxy_wrapper';
 export { ForwarderWrapper } from './contract_wrappers/forwarder_wrapper';
+export { OrderValidatorWrapper } from './contract_wrappers/order_validator_wrapper';
+
+export { TransactionEncoder } from './utils/transaction_encoder';
 
 export {
     ContractWrappersError,
-    EventCallback,
-    ContractEvent,
-    Token,
     IndexedFilterValues,
     BlockRange,
-    OrderFillRequest,
-    ContractEventArgs,
     ContractWrappersConfig,
     MethodOpts,
     OrderTransactionOpts,
     TransactionOpts,
-    LogEvent,
-    DecodedLogEvent,
-    OnOrderStateChangeCallback,
     OrderStatus,
     OrderInfo,
+    EventCallback,
+    DecodedLogEvent,
+    BalanceAndAllowance,
+    OrderAndTraderInfo,
+    TraderInfo,
+    ValidateOrderFillableOpts,
 } from './types';
 
-export {
-    Order,
-    SignedOrder,
-    ECSignature,
-    OrderStateValid,
-    OrderStateInvalid,
-    OrderState,
-    AssetProxyId,
-} from '@0xproject/types';
+export { Order, SignedOrder, AssetProxyId } from '@0xproject/types';
 
 export {
     BlockParamLiteral,
-    FilterObject,
     BlockParam,
     ContractEventArg,
-    LogWithDecodedArgs,
     Provider,
-    TransactionReceipt,
-    TransactionReceiptWithDecodedLogs,
+    ContractAbi,
+    JSONRPCRequestPayload,
+    JSONRPCResponsePayload,
+    JSONRPCErrorCallback,
+    AbiDefinition,
+    LogWithDecodedArgs,
+    FunctionAbi,
+    EventAbi,
+    EventParameter,
+    DecodedLogArgs,
+    MethodAbi,
+    ConstructorAbi,
+    FallbackAbi,
+    DataItem,
+    ConstructorStateMutability,
+    StateMutability,
 } from 'ethereum-types';
 
 export {
@@ -75,8 +80,14 @@ export {
 export {
     ExchangeCancelUpToEventArgs,
     ExchangeAssetProxyRegisteredEventArgs,
+    ExchangeSignatureValidatorApprovalEventArgs,
     ExchangeFillEventArgs,
     ExchangeCancelEventArgs,
     ExchangeEventArgs,
     ExchangeEvents,
 } from './contract_wrappers/generated/exchange';
+
+export { AbstractBalanceAndProxyAllowanceFetcher, AbstractOrderFilledCancelledFetcher } from '@0xproject/order-utils';
+
+export { AssetBalanceAndProxyAllowanceFetcher } from './fetchers/asset_balance_and_proxy_allowance_fetcher';
+export { OrderFilledCancelledFetcher } from './fetchers/order_filled_cancelled_fetcher';
diff --git a/packages/contract-wrappers/src/monorepo_scripts/postpublish.ts b/packages/contract-wrappers/src/monorepo_scripts/postpublish.ts
deleted file mode 100644
index dcb99d0f7..000000000
--- a/packages/contract-wrappers/src/monorepo_scripts/postpublish.ts
+++ /dev/null
@@ -1,8 +0,0 @@
-import { postpublishUtils } from '@0xproject/monorepo-scripts';
-
-import * as packageJSON from '../package.json';
-import * as tsConfigJSON from '../tsconfig.json';
-
-const cwd = `${__dirname}/..`;
-// tslint:disable-next-line:no-floating-promises
-postpublishUtils.runAsync(packageJSON, tsConfigJSON, cwd);
diff --git a/packages/contract-wrappers/src/types.ts b/packages/contract-wrappers/src/types.ts
index 2b3cdc591..e0b12b7c9 100644
--- a/packages/contract-wrappers/src/types.ts
+++ b/packages/contract-wrappers/src/types.ts
@@ -188,3 +188,24 @@ export enum OrderStatus {
     FULLY_FILLED,
     CANCELLED,
 }
+
+export interface TraderInfo {
+    makerBalance: BigNumber;
+    makerAllowance: BigNumber;
+    takerBalance: BigNumber;
+    takerAllowance: BigNumber;
+    makerZrxBalance: BigNumber;
+    makerZrxAllowance: BigNumber;
+    takerZrxBalance: BigNumber;
+    takerZrxAllowance: BigNumber;
+}
+
+export interface OrderAndTraderInfo {
+    orderInfo: OrderInfo;
+    traderInfo: TraderInfo;
+}
+
+export interface BalanceAndAllowance {
+    balance: BigNumber;
+    allowance: BigNumber;
+}
diff --git a/packages/contract-wrappers/src/utils/assert.ts b/packages/contract-wrappers/src/utils/assert.ts
index 183642170..30726c546 100644
--- a/packages/contract-wrappers/src/utils/assert.ts
+++ b/packages/contract-wrappers/src/utils/assert.ts
@@ -1,8 +1,8 @@
 import { assert as sharedAssert } from '@0xproject/assert';
 // HACK: We need those two unused imports because they're actually used by sharedAssert which gets injected here
 import { Schema } from '@0xproject/json-schemas'; // tslint:disable-line:no-unused-variable
-import { assetDataUtils, isValidSignatureAsync } from '@0xproject/order-utils';
-import { ECSignature, Order } from '@0xproject/types'; // tslint:disable-line:no-unused-variable
+import { assetDataUtils, signatureUtils } from '@0xproject/order-utils';
+import { Order } from '@0xproject/types'; // tslint:disable-line:no-unused-variable
 import { BigNumber } from '@0xproject/utils'; // tslint:disable-line:no-unused-variable
 import { Web3Wrapper } from '@0xproject/web3-wrapper';
 import { Provider } from 'ethereum-types';
@@ -18,7 +18,7 @@ export const assert = {
         signature: string,
         signerAddress: string,
     ): Promise<void> {
-        const isValid = await isValidSignatureAsync(provider, orderHash, signature, signerAddress);
+        const isValid = await signatureUtils.isValidSignatureAsync(provider, orderHash, signature, signerAddress);
         sharedAssert.assert(isValid, `Expected order with hash '${orderHash}' to have a valid signature`);
     },
     isValidSubscriptionToken(variableName: string, subscriptionToken: string): void {
diff --git a/packages/contract-wrappers/src/utils/constants.ts b/packages/contract-wrappers/src/utils/constants.ts
index 2df11538c..78441decf 100644
--- a/packages/contract-wrappers/src/utils/constants.ts
+++ b/packages/contract-wrappers/src/utils/constants.ts
@@ -12,4 +12,6 @@ export const constants = {
     UNLIMITED_ALLOWANCE_IN_BASE_UNITS: new BigNumber(2).pow(256).minus(1),
     DEFAULT_BLOCK_POLLING_INTERVAL: 1000,
     ZERO_AMOUNT: new BigNumber(0),
+    ONE_AMOUNT: new BigNumber(1),
+    ETHER_TOKEN_DECIMALS: 18,
 };
diff --git a/packages/contract-wrappers/src/utils/decorators.ts b/packages/contract-wrappers/src/utils/decorators.ts
index 6e77450e8..e17246015 100644
--- a/packages/contract-wrappers/src/utils/decorators.ts
+++ b/packages/contract-wrappers/src/utils/decorators.ts
@@ -1,4 +1,3 @@
-import { RevertReason } from '@0xproject/types';
 import * as _ from 'lodash';
 
 import { AsyncMethod, ContractWrappersError, SyncMethod } from '../types';
@@ -24,7 +23,7 @@ const contractCallErrorTransformer = (error: Error) => {
 const schemaErrorTransformer = (error: Error) => {
     if (_.includes(error.message, constants.INVALID_TAKER_FORMAT)) {
         const errMsg =
-            'Order taker must be of type string. If you want anyone to be able to fill an order - pass ZeroEx.NULL_ADDRESS';
+            'Order taker must be of type string. If you want anyone to be able to fill an order - pass NULL_ADDRESS';
         return new Error(errMsg);
     }
     return error;
@@ -46,7 +45,7 @@ const asyncErrorHandlerFactory = (errorTransformer: ErrorTransformer) => {
         // tslint:disable-next-line:only-arrow-functions
         descriptor.value = async function(...args: any[]): Promise<any> {
             try {
-                const result = await originalMethod.apply(this, args);
+                const result = await originalMethod.apply(this, args); // tslint:disable-line:no-invalid-this
                 return result;
             } catch (error) {
                 const transformedError = errorTransformer(error);
@@ -73,7 +72,7 @@ const syncErrorHandlerFactory = (errorTransformer: ErrorTransformer) => {
         // tslint:disable-next-line:only-arrow-functions
         descriptor.value = function(...args: any[]): any {
             try {
-                const result = originalMethod.apply(this, args);
+                const result = originalMethod.apply(this, args); // tslint:disable-line:no-invalid-this
                 return result;
             } catch (error) {
                 const transformedError = errorTransformer(error);
diff --git a/packages/contract-wrappers/src/utils/exchange_transfer_simulator.ts b/packages/contract-wrappers/src/utils/exchange_transfer_simulator.ts
index 279f2a796..a7c4a238f 100644
--- a/packages/contract-wrappers/src/utils/exchange_transfer_simulator.ts
+++ b/packages/contract-wrappers/src/utils/exchange_transfer_simulator.ts
@@ -34,7 +34,7 @@ const ERR_MSG_MAPPING = {
 };
 
 export class ExchangeTransferSimulator {
-    private _store: AbstractBalanceAndProxyAllowanceLazyStore;
+    private readonly _store: AbstractBalanceAndProxyAllowanceLazyStore;
     private static _throwValidationError(
         failureReason: FailureReason,
         tradeSide: TradeSide,
diff --git a/packages/contract-wrappers/src/utils/filter_utils.ts b/packages/contract-wrappers/src/utils/filter_utils.ts
index 0e73987f7..c05be062c 100644
--- a/packages/contract-wrappers/src/utils/filter_utils.ts
+++ b/packages/contract-wrappers/src/utils/filter_utils.ts
@@ -1,4 +1,4 @@
-import { ConstructorAbi, ContractAbi, EventAbi, FallbackAbi, FilterObject, LogEntry, MethodAbi } from 'ethereum-types';
+import { ContractAbi, EventAbi, FilterObject, LogEntry } from 'ethereum-types';
 import * as ethUtil from 'ethereumjs-util';
 import * as jsSHA3 from 'js-sha3';
 import * as _ from 'lodash';
diff --git a/packages/contract-wrappers/src/utils/transaction_encoder.ts b/packages/contract-wrappers/src/utils/transaction_encoder.ts
new file mode 100644
index 000000000..87cbb43fd
--- /dev/null
+++ b/packages/contract-wrappers/src/utils/transaction_encoder.ts
@@ -0,0 +1,293 @@
+import { schemas } from '@0xproject/json-schemas';
+import { EIP712Schema, EIP712Types, eip712Utils } from '@0xproject/order-utils';
+import { Order, SignedOrder } from '@0xproject/types';
+import { BigNumber } from '@0xproject/utils';
+import _ = require('lodash');
+
+import { ExchangeContract } from '../contract_wrappers/generated/exchange';
+
+import { assert } from './assert';
+
+const EIP712_ZEROEX_TRANSACTION_SCHEMA: EIP712Schema = {
+    name: 'ZeroExTransaction',
+    parameters: [
+        { name: 'salt', type: EIP712Types.Uint256 },
+        { name: 'signerAddress', type: EIP712Types.Address },
+        { name: 'data', type: EIP712Types.Bytes },
+    ],
+};
+
+/**
+ * Transaction Encoder. Transaction messages exist for the purpose of calling methods on the Exchange contract
+ * in the context of another address. For example, UserA can encode and sign a fillOrder transaction and UserB
+ * can submit this to the blockchain. The Exchange context executes as if UserA had directly submitted this transaction.
+ */
+export class TransactionEncoder {
+    private readonly _exchangeInstance: ExchangeContract;
+    constructor(exchangeInstance: ExchangeContract) {
+        this._exchangeInstance = exchangeInstance;
+    }
+    /**
+     * Encodes the transaction data for use with the Exchange contract.
+     * @param data The ABI Encoded 0x Exchange method. I.e fillOrder
+     * @param salt A random value to provide uniqueness and prevent replay attacks.
+     * @param signerAddress The address which will sign this transaction.
+     * @return An unsigned hex encoded transaction for use in 0x Exchange executeTransaction.
+     */
+    public getTransactionHex(data: string, salt: BigNumber, signerAddress: string): string {
+        const exchangeAddress = this._getExchangeContract().address;
+        const executeTransactionData = {
+            salt,
+            signerAddress,
+            data,
+        };
+        const executeTransactionHashBuff = eip712Utils.structHash(
+            EIP712_ZEROEX_TRANSACTION_SCHEMA,
+            executeTransactionData,
+        );
+        const eip721MessageBuffer = eip712Utils.createEIP712Message(executeTransactionHashBuff, exchangeAddress);
+        const messageHex = `0x${eip721MessageBuffer.toString('hex')}`;
+        return messageHex;
+    }
+    /**
+     * Encodes a fillOrder transaction.
+     * @param  signedOrder           An object that conforms to the SignedOrder interface.
+     * @param  takerAssetFillAmount  The amount of the order (in taker asset baseUnits) that you wish to fill.
+     * @return Hex encoded abi of the function call.
+     */
+    public fillOrderTx(signedOrder: SignedOrder, takerAssetFillAmount: BigNumber): string {
+        assert.doesConformToSchema('signedOrder', signedOrder, schemas.signedOrderSchema);
+        assert.isValidBaseUnitAmount('takerAssetFillAmount', takerAssetFillAmount);
+        const abiEncodedData = this._getExchangeContract().fillOrder.getABIEncodedTransactionData(
+            signedOrder,
+            takerAssetFillAmount,
+            signedOrder.signature,
+        );
+        return abiEncodedData;
+    }
+    /**
+     * Encodes a fillOrderNoThrow transaction.
+     * @param  signedOrder           An object that conforms to the SignedOrder interface.
+     * @param  takerAssetFillAmount  The amount of the order (in taker asset baseUnits) that you wish to fill.
+     * @return Hex encoded abi of the function call.
+     */
+    public fillOrderNoThrowTx(signedOrder: SignedOrder, takerAssetFillAmount: BigNumber): string {
+        assert.doesConformToSchema('signedOrder', signedOrder, schemas.signedOrderSchema);
+        assert.isValidBaseUnitAmount('takerAssetFillAmount', takerAssetFillAmount);
+        const abiEncodedData = this._getExchangeContract().fillOrderNoThrow.getABIEncodedTransactionData(
+            signedOrder,
+            takerAssetFillAmount,
+            signedOrder.signature,
+        );
+        return abiEncodedData;
+    }
+    /**
+     * Encodes a fillOrKillOrder transaction.
+     * @param  signedOrder           An object that conforms to the SignedOrder interface.
+     * @param  takerAssetFillAmount  The amount of the order (in taker asset baseUnits) that you wish to fill.
+     * @return Hex encoded abi of the function call.
+     */
+    public fillOrKillOrderTx(signedOrder: SignedOrder, takerAssetFillAmount: BigNumber): string {
+        assert.doesConformToSchema('signedOrder', signedOrder, schemas.signedOrderSchema);
+        assert.isValidBaseUnitAmount('takerAssetFillAmount', takerAssetFillAmount);
+        const abiEncodedData = this._getExchangeContract().fillOrKillOrder.getABIEncodedTransactionData(
+            signedOrder,
+            takerAssetFillAmount,
+            signedOrder.signature,
+        );
+        return abiEncodedData;
+    }
+    /**
+     * Encodes a batchFillOrders transaction.
+     * @param   signedOrders          An array of signed orders to fill.
+     * @param   takerAssetFillAmounts The amounts of the orders (in taker asset baseUnits) that you wish to fill.
+     * @return Hex encoded abi of the function call.
+     */
+    public batchFillOrdersTx(signedOrders: SignedOrder[], takerAssetFillAmounts: BigNumber[]): string {
+        assert.doesConformToSchema('signedOrders', signedOrders, schemas.signedOrdersSchema);
+        _.forEach(takerAssetFillAmounts, takerAssetFillAmount =>
+            assert.isBigNumber('takerAssetFillAmount', takerAssetFillAmount),
+        );
+        const signatures = _.map(signedOrders, signedOrder => signedOrder.signature);
+        const abiEncodedData = this._getExchangeContract().batchFillOrders.getABIEncodedTransactionData(
+            signedOrders,
+            takerAssetFillAmounts,
+            signatures,
+        );
+        return abiEncodedData;
+    }
+    /**
+     * Encodes a batchFillOrKillOrders transaction.
+     * @param   signedOrders          An array of signed orders to fill.
+     * @param   takerAssetFillAmounts The amounts of the orders (in taker asset baseUnits) that you wish to fill.
+     * @return Hex encoded abi of the function call.
+     */
+    public batchFillOrKillOrdersTx(signedOrders: SignedOrder[], takerAssetFillAmounts: BigNumber[]): string {
+        assert.doesConformToSchema('signedOrders', signedOrders, schemas.signedOrdersSchema);
+        _.forEach(takerAssetFillAmounts, takerAssetFillAmount =>
+            assert.isBigNumber('takerAssetFillAmount', takerAssetFillAmount),
+        );
+        const signatures = _.map(signedOrders, signedOrder => signedOrder.signature);
+        const abiEncodedData = this._getExchangeContract().batchFillOrKillOrders.getABIEncodedTransactionData(
+            signedOrders,
+            takerAssetFillAmounts,
+            signatures,
+        );
+        return abiEncodedData;
+    }
+    /**
+     * Encodes a batchFillOrdersNoThrow transaction.
+     * @param   signedOrders          An array of signed orders to fill.
+     * @param   takerAssetFillAmounts The amounts of the orders (in taker asset baseUnits) that you wish to fill.
+     * @return Hex encoded abi of the function call.
+     */
+    public batchFillOrdersNoThrowTx(signedOrders: SignedOrder[], takerAssetFillAmounts: BigNumber[]): string {
+        assert.doesConformToSchema('signedOrders', signedOrders, schemas.signedOrdersSchema);
+        _.forEach(takerAssetFillAmounts, takerAssetFillAmount =>
+            assert.isBigNumber('takerAssetFillAmount', takerAssetFillAmount),
+        );
+        const signatures = _.map(signedOrders, signedOrder => signedOrder.signature);
+        const abiEncodedData = this._getExchangeContract().batchFillOrdersNoThrow.getABIEncodedTransactionData(
+            signedOrders,
+            takerAssetFillAmounts,
+            signatures,
+        );
+        return abiEncodedData;
+    }
+    /**
+     * Encodes a batchCancelOrders transaction.
+     * @param   signedOrders An array of orders to cancel.
+     * @return Hex encoded abi of the function call.
+     */
+    public batchCancelOrdersTx(signedOrders: SignedOrder[]): string {
+        assert.doesConformToSchema('signedOrders', signedOrders, schemas.signedOrdersSchema);
+        const abiEncodedData = this._getExchangeContract().batchCancelOrders.getABIEncodedTransactionData(signedOrders);
+        return abiEncodedData;
+    }
+    /**
+     * Encodes a cancelOrdersUpTo transaction.
+     * @param  targetOrderEpoch Target order epoch.
+     * @return Hex encoded abi of the function call.
+     */
+    public cancelOrdersUpToTx(targetOrderEpoch: BigNumber): string {
+        assert.isBigNumber('targetOrderEpoch', targetOrderEpoch);
+        const abiEncodedData = this._getExchangeContract().cancelOrdersUpTo.getABIEncodedTransactionData(
+            targetOrderEpoch,
+        );
+        return abiEncodedData;
+    }
+    /**
+     * Encodes a cancelOrder transaction.
+     * @param  order An object that conforms to the Order or SignedOrder interface. The order you would like to cancel.
+     * @return Hex encoded abi of the function call.
+     */
+    public cancelOrderTx(order: Order | SignedOrder): string {
+        assert.doesConformToSchema('order', order, schemas.orderSchema);
+        const abiEncodedData = this._getExchangeContract().cancelOrder.getABIEncodedTransactionData(order);
+        return abiEncodedData;
+    }
+    /**
+     * Encodes a marketSellOrders transaction.
+     * @param   signedOrders         An array of signed orders to fill.
+     * @param   takerAssetFillAmount Taker asset fill amount.
+     * @return Hex encoded abi of the function call.
+     */
+    public marketSellOrdersTx(signedOrders: SignedOrder[], takerAssetFillAmount: BigNumber): string {
+        assert.doesConformToSchema('signedOrders', signedOrders, schemas.signedOrdersSchema);
+        assert.isBigNumber('takerAssetFillAmount', takerAssetFillAmount);
+        const signatures = _.map(signedOrders, signedOrder => signedOrder.signature);
+        const abiEncodedData = this._getExchangeContract().marketSellOrders.getABIEncodedTransactionData(
+            signedOrders,
+            takerAssetFillAmount,
+            signatures,
+        );
+        return abiEncodedData;
+    }
+    /**
+     * Encodes a marketSellOrdersNoThrow transaction.
+     * @param   signedOrders         An array of signed orders to fill.
+     * @param   takerAssetFillAmount Taker asset fill amount.
+     * @return Hex encoded abi of the function call.
+     */
+    public marketSellOrdersNoThrowTx(signedOrders: SignedOrder[], takerAssetFillAmount: BigNumber): string {
+        assert.doesConformToSchema('signedOrders', signedOrders, schemas.signedOrdersSchema);
+        assert.isBigNumber('takerAssetFillAmount', takerAssetFillAmount);
+        const signatures = _.map(signedOrders, signedOrder => signedOrder.signature);
+        const abiEncodedData = this._getExchangeContract().marketSellOrdersNoThrow.getABIEncodedTransactionData(
+            signedOrders,
+            takerAssetFillAmount,
+            signatures,
+        );
+        return abiEncodedData;
+    }
+    /**
+     * Encodes a maketBuyOrders transaction.
+     * @param   signedOrders         An array of signed orders to fill.
+     * @param   makerAssetFillAmount Maker asset fill amount.
+     * @return Hex encoded abi of the function call.
+     */
+    public marketBuyOrdersTx(signedOrders: SignedOrder[], makerAssetFillAmount: BigNumber): string {
+        assert.doesConformToSchema('signedOrders', signedOrders, schemas.signedOrdersSchema);
+        assert.isBigNumber('makerAssetFillAmount', makerAssetFillAmount);
+        const signatures = _.map(signedOrders, signedOrder => signedOrder.signature);
+        const abiEncodedData = this._getExchangeContract().marketBuyOrders.getABIEncodedTransactionData(
+            signedOrders,
+            makerAssetFillAmount,
+            signatures,
+        );
+        return abiEncodedData;
+    }
+    /**
+     * Encodes a maketBuyOrdersNoThrow transaction.
+     * @param   signedOrders         An array of signed orders to fill.
+     * @param   makerAssetFillAmount Maker asset fill amount.
+     * @return Hex encoded abi of the function call.
+     */
+    public marketBuyOrdersNoThrowTx(signedOrders: SignedOrder[], makerAssetFillAmount: BigNumber): string {
+        assert.doesConformToSchema('signedOrders', signedOrders, schemas.signedOrdersSchema);
+        assert.isBigNumber('makerAssetFillAmount', makerAssetFillAmount);
+        const signatures = _.map(signedOrders, signedOrder => signedOrder.signature);
+        const abiEncodedData = this._getExchangeContract().marketBuyOrdersNoThrow.getABIEncodedTransactionData(
+            signedOrders,
+            makerAssetFillAmount,
+            signatures,
+        );
+        return abiEncodedData;
+    }
+    /**
+     * Encodes a preSign transaction.
+     * @param hash          Hash to pre-sign
+     * @param signerAddress Address that should have signed the given hash.
+     * @param signature     Proof that the hash has been signed by signer.
+     * @return Hex encoded abi of the function call.
+     */
+    public preSignTx(hash: string, signerAddress: string, signature: string): string {
+        assert.isHexString('hash', hash);
+        assert.isETHAddressHex('signerAddress', signerAddress);
+        assert.isHexString('signature', signature);
+        const abiEncodedData = this._getExchangeContract().preSign.getABIEncodedTransactionData(
+            hash,
+            signerAddress,
+            signature,
+        );
+        return abiEncodedData;
+    }
+    /**
+     * Encodes a setSignatureValidatorApproval transaction.
+     * @param   validatorAddress        Validator contract address.
+     * @param   isApproved              Boolean value to set approval to.
+     * @return Hex encoded abi of the function call.
+     */
+    public setSignatureValidatorApprovalTx(validatorAddress: string, isApproved: boolean): string {
+        assert.isETHAddressHex('validatorAddress', validatorAddress);
+        assert.isBoolean('isApproved', isApproved);
+        const abiEncodedData = this._getExchangeContract().setSignatureValidatorApproval.getABIEncodedTransactionData(
+            validatorAddress,
+            isApproved,
+        );
+        return abiEncodedData;
+    }
+    private _getExchangeContract(): ExchangeContract {
+        return this._exchangeInstance;
+    }
+}
diff --git a/packages/contract-wrappers/src/utils/utils.ts b/packages/contract-wrappers/src/utils/utils.ts
index 689a7ee0a..f7949ec34 100644
--- a/packages/contract-wrappers/src/utils/utils.ts
+++ b/packages/contract-wrappers/src/utils/utils.ts
@@ -1,4 +1,7 @@
 import { BigNumber } from '@0xproject/utils';
+import { Web3Wrapper } from '@0xproject/web3-wrapper';
+
+import { constants } from './constants';
 
 export const utils = {
     getCurrentUnixTimestampSec(): BigNumber {
@@ -8,4 +11,7 @@ export const utils = {
     getCurrentUnixTimestampMs(): BigNumber {
         return new BigNumber(Date.now());
     },
+    numberPercentageToEtherTokenAmountPercentage(percentage: number): BigNumber {
+        return Web3Wrapper.toBaseUnitAmount(constants.ONE_AMOUNT, constants.ETHER_TOKEN_DECIMALS).mul(percentage);
+    },
 };