ChessAnalysis uses Stockfish, the open-source chess engine, for all analysis on this site. Stockfish is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License version 3 (GPLv3), as published by the Free Software Foundation.
Which build we ship
- Stockfish 19, "lite single-threaded" WebAssembly build, from the npm package
stockfishversion 19.0.1 (the stockfish.js port by Nathan Rugg and contributors). - The files are served unmodified from
/engine/sf19.0.1/stockfish-19-lite-single.jsand/engine/sf19.0.1/stockfish-19-lite-single.wasmand run in your browser as a separate Web Worker. They are not combined with the rest of the site's code. - SHA-256:
ccb130d7ff29408531c47d859a49f91d59d4f482d05a53eb1a3231a4f624c91a(js),ee4f115bdb2d32cadf96cada104a05b5ec257d7ad6f57582190b49bc71f096de(wasm).
Source code
- Source of this build: github.com/nmrugg/stockfish.js (release matching npm 19.0.1) and the npm package stockfish@19.0.1.
- Upstream engine: github.com/official-stockfish/Stockfish, release Stockfish 19.
- If a link stops working, email support@chessanalysis.dev and we will send you the complete corresponding source code of the build we serve.
Licence text
The full text of the GNU General Public License version 3 is available at gnu.org/licenses/gpl-3.0. Stockfish comes with no warranty, to the extent permitted by applicable law.
Other open-source components
The board uses react-chessboard (MIT licence) and the rules come from chess.js (BSD 2-Clause licence). Thanks to the Stockfish team and contributors for making the engine freely available.