Source Code

Lichess is free/libre open source software. You can download, read, use and modify every bit of source code.

Main server

• ornicar/lila Main backend and frontend (Scala)
• ornicar/lila modules Backend modules (Scala)
• ornicar/lila ui Frontend modules (TypeScript, Sass)
• ornicar/scalachess Rules of chess and its variants (Scala)
• lichess/compression Compression algorithms for chess moves and clocks (Java)
• ornicar/chessground Frontend chess board (TypeScript)
• niklasf/stockfish.js, niklasf/stockfish.wasm, niklasf/stockfish.pexe Latest Stockfish compiled for browsers (C++, WebAssembly, JavaScript)
• niklasf/chessops Client-side chess and chess variant rules and operations (TypeScript)

External services

• ornicar/lila-ws WebSocket traffic (Scala)
• ornicar/lila-fishnet Fishnet move requests (Scala)
• ornicar/lila-search Search engine (Scala)
• niklasf/lila-openingexplorer Opening explorer (Scala)
• niklasf/lila-tablebase Tablebase (Rust)
• niklasf/lila-push Web Push service (Rust)
• niklasf/fishnet Distributed computer analysis, using ddugovic/Stockfish, a Stockfish fork with chess variant support (Python, C++)
• niklasf/web-boardimage Board thumbnail images (Python)
• niklasf/lila-gif GIF generator for games and positions (Rust)
• ornicar/lichess-oauth-server OAuth server (PHP)
• clarkerubber/irwin AI that learns cheating patterns to help mods (Python)
• niklasf/lila-ip2proxy Query database of known proxy IPs (Rust)

Mobile app

• veloce/lichobile Main mobile app
• veloce/scalachessjs Rules of chess and its variants
• veloce/cordova-plugin-stockfish Cordova interface Stockfish

Docs, utilities, others

• lichess/api HTTP API documentation (read here)
• ornicar/lichess-puzzle-kit Get started with hacking Lichess puzzles
• ornicar/jquery Trimmed down jQuery fork
• ornicar/lichess-db Generator for database.lichess.org (download all rated games)
• careless25/lichess-bot Bridge between HTTP API and chess engines
• clarkerubber/Staunton-Pieces Original 3D rendered pieces, boards and trophies
• arex1337/lichess-daily-puzzle-slack-app Slack app that posts the daily puzzle to the Slack channel in which it is installed

Happy coding!