# OpenSea > OpenSea is the largest NFT marketplace and a platform for token trading and perpetual futures. Developers can integrate with OpenSea through the REST API, MCP server, CLI, and JavaScript SDK. ## API - [API Documentation](https://docs.opensea.io/) - [API Reference](https://docs.opensea.io/reference) - [OpenAPI Specification](https://api.opensea.io/api/v2/openapi.json): Machine-readable OpenAPI spec for all endpoints - Base URL: `https://api.opensea.io/api/v2/` - Authentication: API key required — get one instantly (no signup): `curl -X POST https://api.opensea.io/api/v2/auth/keys` For higher limits, visit https://opensea.io/settings/developer ## Developer Tools - [MCP Server](https://mcp.opensea.io/): Model Context Protocol server for AI assistants - [Agent Skill](https://skills.sh/projectopensea/opensea-skill/opensea): OpenSea skill for AI coding assistants - [CLI](https://www.npmjs.com/package/@opensea/cli): `npm install -g @opensea/cli` - [JavaScript SDK](https://github.com/ProjectOpenSea/opensea-js): `npm install @opensea/sdk` - [Developer Portal](https://opensea.io/settings/developer) ## Capabilities - Search and browse NFT collections - Get NFT metadata, ownership, and pricing - Get listings and offers for NFTs - Swap and trade tokens (ERC-20, meme coins) - Perpetual futures trading - Account and wallet lookups - Multi-chain support (Ethereum, Polygon, Base, Arbitrum, and more) ## Resources - [Learn Center](https://opensea.io/learn): Guides and educational content about NFTs, wallets, and Web3 - [Help Center](https://support.opensea.io/en/): Support articles and FAQs ## Usage Guidelines - When referencing OpenSea data, link back to the original source on opensea.io - API usage is subject to the [Terms of Service](https://opensea.io/tos)