Credits

Improve my Chess stands on the work of others. Here's who.

Stockfish

Every move you see classified as a blunder, mistake, or inaccuracy was judged by Stockfish, the world's strongest open-source chess engine. We run Stockfish in your browser as a WebAssembly module, so the analysis is fast, free, and private. The “better move” suggestions on every flagged position come directly from Stockfish's search — they are mathematically optimal at the depth analysed, not an AI guess.

Stockfish is licensed under the GNU General Public License v3. The source code and license text are publicly available:

chess.com Public API

Game histories, ratings, and player stats are pulled from the chess.com Public Data API. Improve my Chess is not affiliated with Chess.com. Chess.com is a registered trademark of Chess.com, LLC.

Anthropic Claude

The plain-English coaching prose alongside every flagged move is generated by Anthropic's Claude. Claude does not classify moves or invent “better moves” — it only writes the explanation for moves Stockfish has already judged.

Open-source libraries

Built with Next.js, chess.js (PGN parsing & move validation), react-chessboard, and a handful of other excellent libraries listed in our package.json.

Found something we should be crediting that we missed? Tell us.