Build your own marketplace in minutes

OpenSea provides a one-stop shop for creating your own customizable marketplace for your ERC721 or non-fungible token (NFT) project. Allow users to smoothly buy and sell your items, get custom stats and analytics, and earn revenue when your items get traded.


OpenSea Basic Integration

Integrate an existing ERC721 project into OpenSea

This page is designed for developers who have already written their ERC721 contract and wish to integrate it with OpenSea. However, if you're starting fresh, we recommend following the official OpenSea Developer Tutorial.

Metadata API

For OpenSea to pull in off-chain metadata, we need an API to find metadata. To do this, we typically use the tokenURI method in ERC721 (you can learn about exactly how this works here. However, if you've already deployed your contract and didn't implement this method, you can send an API URL to [email protected] that conforms to the metadata standards and has the format:


While your API can have any URL, it is important that it takes in a token ID and returns data in the format described here.