Lichess

About Lichess

Lichess is a free, open-source chess server that provides an API for programmatic access to its platform. The API is built on OpenAPI 3.1.0 and covers account management (reading and writing profile information and preferences), authentication, and other server operations, with some endpoints supporting streamed responses in newline-delimited JSON format.

The API supports two authentication methods: personal access tokens for direct use, and an OAuth2 authorization code flow with PKCE for applications that let users log in with their Lichess account. Access tokens obtained through OAuth2 are long-lived, expected to last about one year, and refresh tokens are not supported. Requests are rate-limited, with a 429 response indicating a limit has been exceeded.

Client libraries are available for Python (including async and MicroPython variants), Java, JavaScript/TypeScript, Rust, and .NET/C#, along with example applications demonstrating OAuth2 login and gameplay. The API is intended for developers building applications, bots, or integrations on top of Lichess, such as chess bots, board interfaces, and third-party clients. Bulk downloads of rated games, puzzles, and evaluated positions are also referenced as available resources.

Key features

• Free, open-source chess server with a public REST API
• OAuth2 authorization code flow with PKCE for user login
• Personal access tokens for quick API access
• Streaming endpoints via newline-delimited JSON (ND-JSON)
• Downloadable datasets of rated games, puzzles, and evaluated positions
• Official client libraries for Python, Java, JavaScript/TypeScript, Rust, and .NET

Frequently asked questions