Seaport.js

Seaport is a new marketplace protocol for safely and efficiently buying and selling NFTs. This is a TypeScript library intended to make interfacing with the contract reasonable and easy.

Synopsis
Installation
Getting Started
- Use Cases
Contributing

Synopsis

This is a TypeScript library to help interface with Seaport. It includes various helper methods and constants that makes interfacing with Seaport easier. These include creating orders, fulfilling orders, doing the necessary balance and approval checks, and more. We recommend taking a look at the Seaport docs to get a better understanding of how the Seaport marketplace works.

Installation

We recommend using nvm to manage Node.js versions. Execute nvm use, if you have nvm installed.

Then, in your project, run:

npm install --save @opensea/seaport-js

Getting Started

Instantiate your instance of seaport using your ethers provider:

Examples

Through a browser provider (i.e. Metamask)

import { Seaport } from "@opensea/seaport-js";
import { ethers } from "ethers";

const provider = new ethers.BrowserProvider(window.ethereum);

const seaport = new Seaport(provider);

Through a RPC Provider (i.e. Alchemy)

import { Seaport } from "@opensea/seaport-js";
import { ethers } from "ethers";

const provider = new ethers.JsonRpcProvider(
  "https://<network>.alchemyapi.io/v2/YOUR-API-KEY",
);

const seaport = new Seaport(provider);

With custom signer

import { Seaport } from "@opensea/seaport-js";
import { ethers } from "ethers";

// Provider must be provided to the signer when supplying a custom signer
const provider = new ethers.JsonRpcProvider(
  "https://<network>.alchemyapi.io/v2/YOUR-API-KEY",
);

const signer = new ethers.Wallet("YOUR_PK", provider);

const seaport = new Seaport(signer);

Look at the relevant definitions in seaport.ts in order to see the different functionality this library offers.

Use Cases

Many of the main core flows return use cases. What this means is that if you were to create an order (a la createOrder), the library helps perform the necessary balance and approval checks based on the offer of the order being created. If the offerer requires approvals on one asset contract, the actions field of the use case would contain an approval action that the user should execute first in order for the trade to succeed in the future.

Examples

Listing an ERC-721 for 10 ETH and fulfilling it

const offerer = "0xf39fd6e51aad88f6f4ce6ab8827279cfffb92266";
const fulfiller = "0x70997970c51812dc3a010c7d01b50e0d17dc79c8";
const { executeAllActions } = await seaport.createOrder(
  {
    offer: [
      {
        itemType: ItemType.ERC721,
        token: "0x8a90cab2b38dba80c64b7734e58ee1db38b8992e",
        identifier: "1",
      },
    ],
    consideration: [
      {
        amount: ethers.parseEther("10").toString(),
        recipient: offerer,
      },
    ],
  },
  offerer,
);

const order = await executeAllActions();

const { executeAllActions: executeAllFulfillActions } =
  await seaport.fulfillOrder({
    order,
    accountAddress: fulfiller,
  });

const transaction = executeAllFulfillActions();

Making an offer for an ERC-721 for 10 WETH and fulfilling it

const offerer = "0xf39fd6e51aad88f6f4ce6ab8827279cfffb92266";
const fulfiller = "0x70997970c51812dc3a010c7d01b50e0d17dc79c8";
const { executeAllActions } = await seaport.createOrder(
  {
    offer: [
      {
        amount: parseEther("10").toString(),
        // WETH
        token: "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2",
      },
    ],
    consideration: [
      {
        itemType: ItemType.ERC721,
        token: "0x8a90cab2b38dba80c64b7734e58ee1db38b8992e",
        identifier: "1",
        recipient: offerer,
      },
    ],
  },
  offerer,
);

const order = await executeAllActions();

const { executeAllActions: executeAllFulfillActions } =
  await seaport.fulfillOrder({
    order,
    accountAddress: fulfiller,
  });

const transaction = executeAllFulfillActions();