Credits and licences
This chess club is built with free and open-source software and open data. Thank you to everyone who made them.
Stockfish (the chess engine)
Stockfish.js 18, © 2026 Chess.com, LLC, based on Stockfish by T. Romstad, M. Costalba, J. Kiiski, G. Linscott and other contributors. Neural network by Linmiao Xu (linrock).
Licence: GNU General Public License v3. The engine runs in your browser. Its complete source code is available at github.com/nmrugg/stockfish.js and github.com/official-stockfish/Stockfish.
chess.js (the rules)
© 2025 Jeff Hlywa. Licence: BSD 2-Clause. Source and licence: github.com/jhlywa/chess.js.
Chess pieces
The "cburnett" piece set by Colin M.L. Burnett, as used by Lichess. Licence: GNU GPL v2 or later.
Puzzles and opening names
Tactics puzzles come from the Lichess puzzle database, and opening names from lichess-org/chess-openings. Both are released into the public domain (CC0).
Fonts
Fredoka and Atkinson Hyperlegible, licensed under the SIL Open Font License 1.1.