Credits and licences
Elopath is built on open-source software, an open human-move model and open chess data. Thank you to their authors.
Elopath is not affiliated with Chess.com or Lichess.
Stockfish
The chess engine behind every analysis (GPL-3.0). It runs unmodified as a separate program; its source code is available at github.com/official-stockfish/Stockfish.
python-chess
Chess rules and PGN handling on the server (GPL-3.0), by Niklas Fiekas and contributors.
Maia 3
The human-move model that shows what players at a rating usually play and powers the practice opponent, by the Computational Social Science Lab, University of Toronto. Its code and the Maia3-79M weights are licensed under the GNU AGPL-3.0. Source code: github.com/CSSLab/maia3 (commit 1e13597); the program that runs it here: /source/maia3_policy.py.
Lichess open database
Practice puzzles, assessment puzzles and evaluation samples come from database.lichess.org, released into the public domain (CC0).
Open-source libraries
Next.js, React, FastAPI, SQLAlchemy, PostgreSQL, Valkey, Celery, chess.js, react-chessboard and many more; the full list with versions and licences is kept with the source code.
Fonts
Geist and Geist Mono (SIL Open Font License 1.1).