OpenSea.js <!-- omit in toc -->

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A JavaScript library for crypto-native ecommerce: buying, selling, and bidding on any cryptogood. With OpenSea.js, you can easily build your own native marketplace for your non-fungible tokens, or NFTs. These can be ERC-721 or ERC-1155 (semi-fungible) items. You don't have to deploy your own smart contracts or backend orderbooks.

Published on GitHub and npm

• Synopsis
• Installation
• Getting Started
  • Fetching Assets
  • Checking Balances and Ownerships
  • Making Offers
  • Bidding on Multiple Assets
  • Bidding on ENS Short Name Auctions
  • Making Listings / Selling Items
  • Creating English Auctions
  • Running Crowdsales
  • Fetching Orders
  • Buying Items
  • Accepting Offers
  • Transferring Items or Coins (Gifting)
• Affiliate Program
  • Referring Listings
  • Referring Offers
  • Custom Affiliate Programs
  • Custom Referral Bounties
• Advanced
  • Purchasing Items for Other Users
  • Bulk Transfers
  • Creating Bundles
  • Using ERC-20 Tokens Instead of Ether
  • Private Auctions
  • Sharing Sale Fees with OpenSea
  • Listening to Events
• Learning More
  • Example Code
• Migrating to version 1.0
• Development Information
• Diagnosing Common Issues

Synopsis

This is the JavaScript SDK for OpenSea, the largest marketplace for crypto collectibles. It allows developers to access the official orderbook, filter it, create buy orders (offers), create sell orders (auctions), create collections of assets to sell at once (bundles), and complete trades programmatically.

For the first time, you can build a cryptocommerce dapp.

You get started by instantiating your own seaport. Then you can create orders off-chain or fulfill orders on-chain, and listen to events (like

ApproveAllAssets

WrapEth

Happy seafaring! ⛵️

Installation

We recommend switching to Node.js version 8.11 to make sure common crypto dependencies work. Execute

nvm use

Then, in your project, run:

bash
npm install --save opensea-js

Install web3 too if you haven't already.

If you run into an error while building the dependencies and you're on a Mac, run this:

xcode-select --install # Install Command Line Tools if you haven't already.
sudo xcode-select --switch /Library/Developer/CommandLineTools # Enable command line tools
sudo npm explore npm -g -- npm install [email protected] # (Optional) update node-gyp

Getting Started

To get started, create a new OpenSeaJS client, called an OpenSeaPort 🚢, using your Web3 provider:

import * as Web3 from 'web3'
import { OpenSeaPort, Network } from 'opensea-js'

// This example provider won't let you make transactions, only read-only calls:
const provider = new Web3.providers.HttpProvider('https://mainnet.infura.io')
const seaport = new OpenSeaPort(provider, {
  networkName: Network.Main
})

NOTE: Using the sample Infura provider above won't let you authorize transactions, which are needed when approving and trading assets and currency. To make transactions, you need a provider with a private key or mnemonic set.

In a browser with web3 or an extension like MetaMask or Dapper, you can use

window.ethereum

window.web3.currentProvider

Fetching Assets

Assets are items on OpenSea. They can be non-fungible (conforming to standards like ERC721), semi-fungible (like ERC1155 assets), and even fungible (ERC20).

Assets are represented by the

Asset

/**
 * Simple, unannotated non-fungible asset spec
 */
export interface Asset {
  // The asset's token ID, or null if ERC-20
  tokenId: string | null,
  // The asset's contract address
  tokenAddress: string,
  // The Wyvern schema name (defaults to "ERC721") for this asset
  schemaName?: WyvernSchemaName,
  // Optional for ENS names
  name?: string,
  // Optional for fungible items
  decimals?: number
}

The

Asset

WyvernSchemaName

import { WyvernSchemaName } from "opensea-js/lib/types"

You can fetch an asset using the

OpenSeaAPI

OpenSeaAsset

OpenSeaAsset

Asset

const asset: OpenSeaAsset = await seaport.api.getAsset({
  tokenAddress, // string
  tokenId, // string | number | null
})

Note that fungible ERC20 assets have

null

Checking Balances and Ownerships

The nice thing about the

Asset

Once you have an

Asset

const asset = {
  tokenAddress: "0x06012c8cf97bead5deae237070f9587f8e7a266d", // CryptoKitties
  tokenId: "1", // Token ID
}

const balance = await seaport.getAssetBalance({
  accountAddress, // string
  asset, // Asset
})
const ownsKitty = balance.greaterThan(0)

You can use this same method for fungible ERC-20 tokens like wrapped ETH (WETH). As a convenience, you can use this fungible wrapper for checking fungible balances:

const balanceOfWETH = await seaport.getTokenBalance({
  accountAddress, // string
  tokenAddress: "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2"
})

Making Offers

Once you have your asset, you can do this to make an offer on it:

// Token ID and smart contract address for a non-fungible token:
const { tokenId, tokenAddress } = YOUR_ASSET
// The offerer's wallet address:
const accountAddress = "0x1234..."

const offer = await seaport.createBuyOrder({
  asset: {
    tokenId,
    tokenAddress,
    schemaName // WyvernSchemaName. If omitted, defaults to 'ERC721'. Other options include 'ERC20' and 'ERC1155'
  },
  accountAddress,
  // Value of the offer, in units of the payment token (or wrapped ETH if none is specified):
  startAmount: 1.2,
})

When you make an offer on an item owned by an OpenSea user, that user will automatically get an email notifying them with the offer amount, if it's above their desired threshold.

Bidding on Multiple Assets

You can also make an offer on a bundle of assets. This could also be used for creating a bounty for whoever can acquire a list of items. Here's how you do it:

const assets = YOUR_ASSETS
const offer = await seaport.createBundleBuyOrder({
  assets,
  accountAddress,
  startAmount: 2.4,
  // Optional expiration time for the order, in Unix time (seconds):
  expirationTime: Math.round(Date.now() / 1000 + 60 * 60 * 24) // One day from now
})

When you bid on multiple assets, an email will be sent to the owner if a bundle exists on OpenSea that contains the assets. In the future, OpenSea will send emails to multiple owners if the assets aren't all owned by the same wallet.

Bidding on ENS Short Name Auctions

The Ethereum Name Service (ENS) is auctioning short (3-6 character) names that can be used for labeling wallet addresses and more. Learn more on the ENS FAQ.

To bid, you must use the ENS Short Name schema:

const {
  tokenId,
  // Token address should be `0xfac7bea255a6990f749363002136af6556b31e04` on mainnet
  tokenAddress,
  // Name must have `.eth` at the end and correspond with the tokenId
  name
} = ENS_ASSET // You can get an ENS asset from `seaport.api.getAsset(...)`

const offer = await seaport.createBuyOrder({
  asset: {
    tokenId,
    tokenAddress,
    name,
    // Only needed for the short-name auction, not ENS names
    // that have been sold once already:
    schemaName: "ENSShortNameAuction"
  },
  // Your wallet address (the bidder's address):
  accountAddress: "0x1234..."
  // Value of the offer, in wrapped ETH:
  startAmount: 1.2,
})

Making Listings / Selling Items

To sell an asset, call

createSellOrder

startAmount

endAmount

endAmount

expirationTime

// Expire this auction one day from now.
// Note that we convert from the JavaScript timestamp (milliseconds):
const expirationTime = Math.round(Date.now() / 1000 + 60 * 60 * 24)

const listing = await seaport.createSellOrder({
  asset: {
    tokenId,
    tokenAddress,
  },
  accountAddress,
  startAmount: 3,
  // If endAmount is specified, the order will decline in value to that amount until expirationTime. Otherwise, it's a fixed-price order:
  endAmount: 0.1,
  expirationTime
})

The units for

startAmount

endAmount

See Listening to Events to respond to the setup transactions that occur the first time a user sells an item.

Creating English Auctions

English Auctions are auctions that start at a small amount (we recommend even doing 0!) and increase with every bid. At expiration time, the item sells to the highest bidder.

To create an English Auction, create a listing that waits for the highest bid by setting

waitForHighestBid

true

// Create an auction to receive Wrapped Ether (WETH). See note below.
const paymentTokenAddress = "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2"

const startAmount = 0 // The minimum amount to sell for, in normal units (e.g. ETH)
const auction = await seaport.createSellOrder({
  asset: {
    tokenId,
    tokenAddress,
  },
  accountAddress,
  startAmount,
  expirationTime,
  paymentTokenAddress,
  waitForHighestBid: true
})

Note that auctions aren't supported with Ether directly due to limitations in Ethereum, so you have to use an ERC20 token, like Wrapped Ether (WETH), a stablecoin like DAI, etc. See Using ERC-20 Tokens Instead of Ether for more info.

Running Crowdsales

You can now sell items to users without having to pay gas to mint them!

To create a presale or crowdsale and create batches of sell orders for a single asset factory, first follow the tutorial for creating your crowdsale contract.

Then call

createFactorySellOrders

numberOfOrders

// Expire these auctions one day from now
const expirationTime = Math.round(Date.now() / 1000 + 60 * 60 * 24)

const sellOrders = await seaport.createFactorySellOrders({
  assetId: ASSET_OPTION_ID,
  factoryAddress: FACTORY_CONTRACT_ADDRESS,
  accountAddress,
  startAmount,
  endAmount,
  expirationTime,
  // Will create 100 sell orders in parallel batches of 10, to speed things up:
  numberOfOrders: 100
})

Here's an example script you can use to mint items.

NOTE: If

numberOfOrders

apiKey

Games using this method include Coins & Steel and a couple in stealth :) If you have questions or want support, contact us at [email protected] (or in Discord).

Fetching Orders

To retrieve a list of offers and auction on an asset, you can use an instance of the

OpenSeaAPI

import { OrderSide } from 'opensea-js/lib/types'

// Get offers (bids), a.k.a. orders where side == 0
const { orders, count } = await seaport.api.getOrders({
  asset_contract_address: tokenAddress,
  token_id: token_id,
  side: OrderSide.Buy
})
// Get page 2 of all auctions, a.k.a. orders where side == 1
const { orders, count } = await seaport.api.getOrders({
  asset_contract_address: tokenAddress,
  token_id: token_id,
  side: OrderSide.Sell
}, 2)

Note that the listing price of an asset is equal to the

currentPrice

To learn more about signatures, makers, takers, listingTime vs createdTime and other kinds of order terminology, please read the Terminology Section of the API Docs.

The available API filters for the orders endpoint is documented in the

OrderJSON

/**
   * Attrs used by orderbook to make queries easier
   * More to come soon!
   */
  maker?: string, // Address of the order's creator
  taker?: string, // The null address if anyone is allowed to take the order
  side?: OrderSide, // 0 for offers, 1 for auctions
  owner?: string, // Address of owner of the order's asset
  sale_kind?: SaleKind, // 0 for fixed-price, 1 for Dutch auctions
  asset_contract_address?: string, // Contract address for order's asset
  token_id?: number | string,
  token_ids?: Array,
  listed_after?: number | string, // This means listing_time > value in seconds
  listed_before?: number | string, // This means listing_time <= value in seconds

  // For pagination
  limit?: number,
  offset?: number,

Buying Items

To buy an item , you need to fulfill a sell order. To do that, it's just one call:

const order = await seaport.api.getOrder({ side: OrderSide.Sell, ... })
const accountAddress = "0x..." // The buyer's wallet address, also the taker
const transactionHash = await this.props.seaport.fulfillOrder({ order, accountAddress })

Note that the

fulfillOrder

TransactionCreated

If the order is a sell order (

order.side === OrderSide.Sell

Accepting Offers

Similar to fulfilling sell orders above, you need to fulfill a buy order on an item you own to receive the tokens in the offer.

const order = await seaport.api.getOrder({ side: OrderSide.Buy, ... })
const accountAddress = "0x..." // The owner's wallet address, also the taker
await this.props.seaport.fulfillOrder({ order, accountAddress })

If the order is a buy order (

order.side === OrderSide.Buy

Transferring Items or Coins (Gifting)

A handy feature in OpenSea.js is the ability to transfer any supported asset (fungible or non-fungible tokens) in one line of JavaScript.

To transfer an ERC-721 asset or an ERC-1155 asset, it's just one call:

const transactionHash = await seaport.transfer({
  asset: { tokenId, tokenAddress },
  fromAddress, // Must own the asset
  toAddress
})

For fungible ERC-1155 assets, you can set

schemaName

quantity

const transactionHash = await seaport.transfer({
  asset: {
    tokenId,
    tokenAddress,
    schemaName: "ERC1155"
  },
  fromAddress, // Must own the asset
  toAddress,
  quantity: 2,
})

To transfer fungible assets without token IDs, like ERC20 tokens, you can pass in an

OpenSeaFungibleToken

asset

schemaName

quantity

Example for transfering 2 DAI ($2) to another address:

const paymentToken = (await seaport.api.getPaymentTokens({ symbol: 'DAI'})).tokens[0]
const quantity = new BigNumber(Math.pow(10, paymentToken.decimals)).times(2)
const transactionHash = await seaport.transfer({
  asset: {
    tokenId: null,
    tokenAddress: paymentToken.address,
    schemaName: "ERC20"
  },
  fromAddress, // Must own the tokens
  toAddress,
  quantity
})

For more information, check out the documentation for WyvernSchemas on https://projectopensea.github.io/opensea-js/.

Affiliate Program

OpenSea.js allows to you easily create an affiliate program in just a few lines of JavaScript! It's the crypto-equivalent of bounty hunting, and best of all, it's fully paid for by OpenSea so you can keep all of your winnings 💰

If you want to be an affiliate, you can use this to win at least 1% of the sale price of any listing, both for assets and bundles.

Referring Listings

You can instantly create an affiliate program for your assets by just passing in one more parameter when fulfilling orders... and OpenSea will pay for it! Whenever someone refers a sale or the acceptance of an offer, you can add a

referrerAddress

const referrerAddress = "0x..." // The referrer's wallet address
await this.props.seaport.fulfillOrder({ order, accountAddress, referrerAddress })

This works for buying assets and bundles, along with accepting bids that had no referrer attached to them (see below).

As long as the referrer hasn't referred the buyer before, OpenSea will send the referrer an email congradulating them, along with 1% of the item's sale price. If you'd like to be able to refer the same user for multiple purchases, contact us at [email protected]a.io (or in Discord).

Referring Offers

Now you can also refer offers on assets! When the seller accepts the offer, the referrer will get credit:

const referrerAddress = "0x..." // The referrer's wallet address
await this.props.seaport.createBuyOrder({
  asset: {
    tokenId,
    tokenAddress,
  },
  accountAddress, // Address of the bidder
  startAmount: 1.2,
  referrerAddress // Address of the referrer
})

The same thing works for

createBundleBuyOrder

Custom Affiliate Programs

You can use

createBuyOrder({ referrerAddress })

When buyers place offers or bids on an asset, the referrers will automatically be recorded on OpenSea.io. Then, you can use the Orderbook API to inspect the

metadata

referrerAddress

metadata

Custom Referral Bounties

Sellers can customize the bounties they add to their items when listing them for sale. By default, OpenSea will pay referrers 1% and sellers pay them nothing, but sellers can increase this up to the full OpenSea fee (currently 2.5% for most assets) for both assets and bundles:

// Price the Genesis CryptoKitty at 100 ETH
const startAmount = 100
// Reward referrers with 10% of the final sale price,
// or 10 ETH in this case
const extraBountyPercent = 10
// The final bounty will be 10% + 1% from OpenSea, or 11 ETH!

const auction = await seaport.createSellOrder({
  tokenAddress: "0x06012c8cf97bead5deae237070f9587f8e7a266d", // CryptoKitties
  tokenId: "1", // Token ID
  accountAddress: OWNERS_WALLET_ADDRESS,
  startAmount,
  extraBountyBasisPoints: extraBountyPercent * 100
})

NOTE: The final bounty in the example above will be 10% from the seller plus 1% from OpenSea, or 11 ETH in total!

Developers can request to increase the OpenSea fee to allow for higher bounties - by default, it's capped at 2.5%. If you have any questions, contact us at [email protected] (or in Discord), or join the program at https://opensea.io/account#referrals.

Advanced

Interested in purchasing for users server-side or with a bot, making bundling items together, or making bids in different ERC-20 tokens? OpenSea.js can help with that.

Purchasing Items for Other Users

You can buy and transfer an item to someone else in one step! Just pass the

recipientAddress

const order = await seaport.api.getOrder({ side: OrderSide.Sell, ... })
await this.props.seaport.fulfillOrder({
  order,
  accountAddress, // The address of your wallet, which will sign the transaction
  recipientAddress // The address of the recipient, i.e. the wallet you're purchasing on behalf of
})

If the order is a sell order (

order.side === OrderSide.Sell

recipientAddress

OrderSide.Buy

recipientAddress

Bulk Transfers

A handy feature in OpenSea.js is the ability to transfer multiple items at once in a single transaction. This works by grouping together as many

transferFrom

To make a bulk transfer, it's just one call:

const assets: Array = [...]

const transactionHash = await seaport.transferAll({
  assets,
  fromAddress, // Must own all the assets
  toAddress
})

This will automatically approve the assets for trading and confirm the transaction for sending them.

Creating Bundles

You can also create bundles of assets to sell at the same time! If the owner has approved all the assets in the bundle already, only a signature is needed to create it.

To make a bundle, it's just one call:

const assets: Array = [...]

const bundle = await seaport.createBundleSellOrder({
  bundleName, bundleDescription, bundleExternalLink,
  assets, accountAddress, startAmount, endAmount,
  expirationTime, paymentTokenAddress
})

The parameters

bundleDescription

bundleExternalLink

expirationTime

endAmount

startAmount

createSellOrder

The parameter

paymentTokenAddress

undefined

null

Wait what, you can use other currencies than ETH?

Using ERC-20 Tokens Instead of Ether

Here's an example of listing the Genesis CryptoKitty for $100! No more needing to worry about the exchange rate:

// Token address for the DAI stablecoin, which is pegged to $1 USD
const paymentTokenAddress = "0x89d24a6b4ccb1b6faa2625fe562bdd9a23260359"

// The units for startAmount and endAmount are now in DAI, so $100 USD
const auction = await seaport.createSellOrder({
  tokenAddress: "0x06012c8cf97bead5deae237070f9587f8e7a266d", // CryptoKitties
  tokenId: "1", // Token ID
  accountAddress: OWNERS_WALLET_ADDRESS,
  startAmount: 100,
  paymentTokenAddress
})

You can use

getPaymentTokens

const token = (await seaport.api.getPaymentTokens({ symbol: 'MANA'})).tokens[0]

const order = await seaport.api.getOrders({
  side: OrderSide.Sell,
  payment_token_address: token.address
})

Fun note: soon, all ERC-20 tokens will be allowed! This will mean you can create crazy offers on crypto collectibles using your own ERC-20 token. However, opensea.io will only display offers and auctions in ERC-20 tokens that it knows about, optimizing the user experience of order takers. Orders made with the following tokens will be shown on OpenSea:

• MANA, Decentraland's currency: https://etherscan.io/token/0x0f5d2fb29fb7d3cfee444a200298f468908cc942
• DAI, Maker's stablecoin, pegged to $1 USD: https://etherscan.io/token/0x89d24a6b4ccb1b6faa2625fe562bdd9a23260359
• And tons more! See the "Currencies" list in the sidebar on https://opensea.io/assets for a full list, or contact us to add yours: Discord

Private Auctions

Now you can make auctions and listings that can only be fulfilled by an address or email of your choosing. This allows you to negotiate a price in some channel and sell for your chosen price on OpenSea, without having to trust that the counterparty will abide by your terms!

Here's an example of listing a Decentraland parcel for 10 ETH with a specific buyer address allowed to take it. No more needing to worry about whether they'll give you enough back!

// Address allowed to buy from you
const buyerAddress = "0x123..."

const listing = await seaport.createSellOrder({
  tokenAddress: "0xf87e31492faf9a91b02ee0deaad50d51d56d5d4d", // Decentraland
  tokenId: "115792089237316195423570985008687907832853042650384256231655107562007036952461", // Token ID
  accountAddress: OWNERS_WALLET_ADDRESS,
  startAmount: 10,
  buyerAddress
})

Sharing Sale Fees with OpenSea

We share fees for successful sales with game developers, relayers, and affiliates using the OpenSea orderbook. Developers can customize the fee amount to apply to buyers and/or sellers.

See Affiliate Program above for how to register referrers for sales.

More information will appear here when our redesigned affiliate program is ready. In the meantime, contact us at [email protected] (or in Discord), or use our legacy affiliate program at https://opensea.io/account#referrals.

Listening to Events

Events are fired whenever transactions or orders are being created, and when transactions return receipts from recently mined blocks on the Ethereum blockchain.

Our recommendation is that you "forward" OpenSea events to your own store or state management system. Here's an example of doing that with a Redux action:

import { EventType } from 'opensea-js'
import * as ActionTypes from './index'
import { openSeaPort } from '../globalSingletons'

// ...
handleSeaportEvents() {
  return async function(dispatch, getState) {
    openSeaPort.addListener(EventType.TransactionCreated, ({ transactionHash, event }) => {
      console.info({ transactionHash, event })
      dispatch({ type: ActionTypes.SET_PENDING_TRANSACTION_HASH, hash: transactionHash })
    })
    openSeaPort.addListener(EventType.TransactionConfirmed, ({ transactionHash, event }) => {
      console.info({ transactionHash, event })
      // Only reset your exchange UI if we're finishing an order fulfillment or cancellation
      if (event == EventType.MatchOrders || event == EventType.CancelOrder) {
        dispatch({ type: ActionTypes.RESET_EXCHANGE })
      }
    })
    openSeaPort.addListener(EventType.TransactionDenied, ({ transactionHash, event }) => {
      console.info({ transactionHash, event })
      dispatch({ type: ActionTypes.RESET_EXCHANGE })
    })
    openSeaPort.addListener(EventType.TransactionFailed, ({ transactionHash, event }) => {
      console.info({ transactionHash, event })
      dispatch({ type: ActionTypes.RESET_EXCHANGE })
    })
    openSeaPort.addListener(EventType.InitializeAccount, ({ accountAddress }) => {
      console.info({ accountAddress })
      dispatch({ type: ActionTypes.INITIALIZE_PROXY })
    })
    openSeaPort.addListener(EventType.WrapEth, ({ accountAddress, amount }) => {
      console.info({ accountAddress, amount })
      dispatch({ type: ActionTypes.WRAP_ETH })
    })
    openSeaPort.addListener(EventType.UnwrapWeth, ({ accountAddress, amount }) => {
      console.info({ accountAddress, amount })
      dispatch({ type: ActionTypes.UNWRAP_WETH })
    })
    openSeaPort.addListener(EventType.ApproveCurrency, ({ accountAddress, tokenAddress }) => {
      console.info({ accountAddress, tokenAddress })
      dispatch({ type: ActionTypes.APPROVE_WETH })
    })
    openSeaPort.addListener(EventType.ApproveAllAssets, ({ accountAddress, proxyAddress, tokenAddress }) => {
      console.info({ accountAddress, proxyAddress, tokenAddress })
      dispatch({ type: ActionTypes.APPROVE_ALL_ASSETS })
    })
    openSeaPort.addListener(EventType.ApproveAsset, ({ accountAddress, proxyAddress, tokenAddress, tokenId }) => {
      console.info({ accountAddress, proxyAddress, tokenAddress, tokenId })
      dispatch({ type: ActionTypes.APPROVE_ASSET })
    })
    openSeaPort.addListener(EventType.CreateOrder, ({ order, accountAddress }) => {
      console.info({ order, accountAddress })
      dispatch({ type: ActionTypes.CREATE_ORDER })
    })
    openSeaPort.addListener(EventType.OrderDenied, ({ order, accountAddress }) => {
      console.info({ order, accountAddress })
      dispatch({ type: ActionTypes.RESET_EXCHANGE })
    })
    openSeaPort.addListener(EventType.MatchOrders, ({ buy, sell, accountAddress }) => {
      console.info({ buy, sell, accountAddress })
      dispatch({ type: ActionTypes.FULFILL_ORDER })
    })
    openSeaPort.addListener(EventType.CancelOrder, ({ order, accountAddress }) => {
      console.info({ order, accountAddress })
      dispatch({ type: ActionTypes.CANCEL_ORDER })
    })
  }
}

To remove all listeners and start over, just call

seaport.removeAllListeners()

Learning More

Auto-generated documentation for each export is available here.

If you need extra help, support is free! Contact the OpenSea devs. They're available every day on Discord in the

#developers

Example Code

Check out the Ship's Log, built with the SDK, which shows the recent orders in the OpenSea orderbook.

You can view a live demo here! Also check out the Mythereum marketplace, which is entirely powered by OpenSea.js.

Migrating to version 1.0

See the Changelog.

Development Information

Setup

Node >= v8.11.2 required.

Before any development, install the required NPM dependencies:

npm install

And install TypeScript if you haven't already:

npm install -g tslint typescript

Build

Then, lint and build the library into the

lib

npm run build

Or run the tests:

bash
npm test

Note that the tests require access to both Infura and the OpenSea API. The timeout is adjustable via the

test

package.json

Generate Documentation

Generate html docs, also available for browsing here:

bash
npm run docsHtml

Or generate markdown docs available for browsing on git repos:

bash
npm run docsMarkdown

Due to a markdown theme typescript issue,

docs

bash
npm run docs

Contributing

Contributions welcome! Please use GitHub issues for suggestions/concerns - if you prefer to express your intentions in code, feel free to submit a pull request.

Diagnosing Common Issues

• Is the

  expirationTime

  in future? If not, change it to a time in the future.

• Are the input addresses all strings? If not, convert them to strings.

• Is your computer's internal clock accurate? If not, try enabling automatic clock adjustment locally or following this tutorial to update an Amazon EC2 instance.

• Are you attempting to purchase a token that's unpurchasable on OpenSea? If so, contact us Discord in the

  #developers

  channel and we'll help to diagnose the issue.