Credits and licenses

Chessoria is built on free software and open data. Thanks to their authors.

Stockfish engine

Analysis uses Stockfish 19 lite (WebAssembly), running in your browser. Stockfish is free software under the GPL-3.0 license: the license text ships with the engine, and its source code is available.

License text stockfish.js source code

Libraries

chess.js: game rules, PGN and FEN (BSD-2-Clause license).
react-chessboard: interactive board and cburnett-style pieces (MIT license).

Data

Opening names: Lichess chess-openings database, released into the public domain (CC0).