satranc.yasinalev.com

Licences

This site runs on software, drawings and data that others share freely. Here is who made each part and the licence it comes under.

Stockfish 19: the computer opponent

The opponent on the play page is Stockfish 19, by the Stockfish developers (see the AUTHORS file in the source archive). It is free software under the GNU General Public License version 3 (GPL-3).

Its files are used unmodified and run as a separate program, in their own Web Worker. The WebAssembly packaging is by Nathan Rugg and Chess.com (nmrugg/stockfish.js).

Stockfish comes with no warranty. The GPL-3’s disclaimer:

THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, REPAIR OR CORRECTION.

The full text of the GPL-3 (Copying.txt)

The source of Stockfish

As the GPL-3 asks, the complete source of the files that run here is on this site:

Other parts of the site

  • chess.js 1.4.0: the rules of chess (legal moves, check, mate, draws). BSD-2-Clause, Copyright (c) 2025, Jeff Hlywa.
  • The pieces: drawings by Colin M. L. Burnett (Cburnett), Wikimedia Commons. The author offers a choice of licences; this site uses them under the BSD licence. The licence of the pieces
  • The puzzles: the Lichess puzzle database. It is public domain under CC0; we credit it by choice, with thanks.
  • Preact 10.29.8 and @preact/signals 2.11.3: how the pages are built. MIT licence.
  • The fonts Lexend and IBM Plex Mono: SIL Open Font License 1.1.

The full text of every licence but Stockfish’s is in one file: third-party-licenses.txt