Open-source acknowledgements
ChessCoda stands on outstanding open-source chess software. The components below run as separate server-side programs, at arm's length from our own code, and we gratefully credit the people who build them.
Pocket TTS (Kyutai) CC BY 4.0
A small text-to-speech model that runs on a CPU. ChessCoda uses it server-side to voice the coach's walkthroughs in French and German with its built-in voices; the model and the voices are published by Kyutai.
Stockfish GPL-3.0
The strongest open-source chess engine, used for position evaluation and best-move analysis. Stockfish runs server-side as a separate engine process, communicating over the standard UCI protocol.
Maia-3 (Maia Chess, by CSSLab at the University of Toronto) AGPL-3.0
A neural-network chess model trained to predict how human players of different strengths actually play. ChessCoda runs Maia-3 server-side as a separate UCI process via our published open-source wrapper, maia3-policy-uci; it is never linked into our application code. The model weights are the Maia3-79M checkpoint published by CSSLab.
Maia-2 (Maia Chess, by CSSLab at the University of Toronto) MIT
The human-like chess model behind the local sparring personas in the ChessCoda iOS app. The published Maia-2 rapid checkpoint is converted to Core ML and runs entirely on the phone; its 23M weights ship inside the app unchanged in meaning, only in format.
ChessKit MIT
The Swift chess rules library the ChessCoda iOS app uses for legal moves, notation and game records.
Lichess open puzzle database CC0 (public domain)
Practice puzzles in ChessCoda are derived from the freely published Lichess puzzle database.
The ChessCoda Coach Engine
The ChessCoda platform and the ChessCoda Coach Engine, the technology that turns engine analysis into personal coaching, are proprietary software owned by ChessCoda. They are not derived from the open-source components above and are not covered by their licenses. Stockfish and Maia are independent projects; their mention here is attribution, not endorsement.