Chessant is built on excellent open-source software and open content. This page credits that work and records the licenses it is used under, as those licenses require.
Chess engine: Stockfish
Chessant's play strength, game review, and analysis are powered by Stockfish, one of the strongest chess engines in the world. Stockfish is free software licensed under the GNU General Public License, version 3 (GPL-3.0).
Chessant uses the official Stockfish WebAssembly build unmodified. It runs entirely inside your own browser as a separate worker; your games are never uploaded to a server to be analyzed. In keeping with the GPL, the complete corresponding source for Stockfish is publicly available:
- Source code: github.com/official-stockfish/Stockfish
- WebAssembly package used: the "stockfish" npm package
- License text: GNU General Public License v3.0
Stockfish is a separate program that Chessant communicates with by passing messages. It is not modified and not combined into Chessant's own code.
Puzzles
The puzzle library is a sample of the Lichess open puzzle database, released into the public domain under the Creative Commons CC0 dedication. Thank you to Lichess and its community for making it free for everyone.
Sound effects
The piece move and capture sounds are derived from "chess_move_on_alabaster" by mh2o on Freesound, released under the Creative Commons CC0 public-domain dedication. The musical cues (check, checkmate, victory, and the rest) are original sounds generated for Chessant.
Open-source libraries
These permissively-licensed libraries are used to build Chessant:
Everything else
The Chessant name and logo, the piece and board designs, visual effects, lessons, opening book, and all original code are the property of Chessant. Emoji shown in effects and badges are rendered by your device's own font.