Open-source licences and credits
ChessNotes is built on free and open-source software and on open chess data. This page lists what we use, who made it, the licence it comes under and where to get its source code.
Last updated: 1 October 2026
1. Chess engine: Stockfish
The engine analysis in ChessNotes is Stockfish 19, in the single-threaded WebAssembly builds of Stockfish.js 19.0.0: the full build (with the big neural network) on computers, the "lite" build (with a 1 MB network) on phones and tablets, or when the full one can't run. Your browser downloads the build it needs from chessnotes.app/stockfish/ the first time you analyse a position and runs it on your device, as a separate program in a Web Worker: ChessNotes only sends it positions and reads its answers through the UCI text protocol.
Licence and authors
- Stockfish is free software under the GNU General Public License, version 3 (GPLv3). Copyright © 2004-2026 The Stockfish developers: Tord Romstad, Marco Costalba, Joona Kiiski, Gary Linscott and all the contributors. WebAssembly port: Stockfish.js by Nathan Rugg, © Chess.com, LLC, GPLv3. Neural networks: nn-1a298aa575a0 (Stockfish 19 default network) and the lite network nn-61e7af4bb97d by sscg13.
- Stockfish comes with absolutely no warranty, to the extent permitted by law. You are free to copy, modify and redistribute it under the terms of the GPLv3.
Exact version and source code
- We serve the upstream files unmodified (byte-for-byte, checked with SHA-256). Their complete corresponding source code (C++ sources and build scripts) is at commit 9cb3e50 of nmrugg/stockfish.js (tag v19.0.0) (download); the upstream engine is official-stockfish/Stockfish. The two neural networks are on the Stockfish network server.
- File list and checksums: Stockfish notice. If a link stops working, write to us and we will send you the same source code free of charge.
2. Chess pieces
The pieces on every board are the "Cburnett" set by Colin M.L. Burnett, as shipped by the react-chessboard library, used under the BSD 3-clause licence (the author also offers them under GFDL, CC BY-SA 3.0 and GPL). Credits and licence text: chess-pieces.txt; originals on Wikimedia Commons.
3. Fonts
The website uses Geist, © 2024 The Geist Project Authors (vercel/geist-font), under the SIL Open Font License 1.1. We host the font files ourselves. The app uses your device's system font.
4. JavaScript libraries
The app's code includes these open-source packages, unmodified: React and React DOM (MIT, © Facebook, Inc. and its affiliates), React Router (MIT, © React Training LLC, Remix Software Inc. and Shopify Inc.), react-helmet-async (Apache-2.0), chess.js (BSD-2-Clause, © Jeff Hlywa), react-chessboard (MIT, © Ryan Gregory) with react-dnd (MIT, © Dan Abramov), the Firebase JavaScript SDK (Apache License 2.0, © Google LLC), prop-types (MIT) and their dependencies. The full list, with every copyright notice and licence text, is in THIRD-PARTY-NOTICES.txt.
5. Chess data and services
Some features read public data from other chess sites, from your browser or through our server. We thank them; they are independent services with their own terms.
Lichess
- Cloud evaluations and opening-explorer statistics come from lichess.org, a free, open-source chess server. The Lichess game database is released under Creative Commons CC0. Lichess terms of service.
- Lichess studies belong to their authors. When you import a public study, ChessNotes downloads it through the official Lichess export on your request and keeps it in your private repertoire for your own study; we do not republish it. Each study links back to its page on Lichess.
Opening names
The names of the openings and variations in "Repertoires from your games" come from the Lichess chess-openings dataset (commit c67912b), dedicated to the public domain under Creative Commons CC0 1.0. The app ships a table derived from it (position to variation name); see THIRD-PARTY-NOTICES.txt.
Chess.com
Your games are read from the Chess.com Published-Data API, which serves public data only.
6. Trademarks
Chess.com, Lichess, Chessable, MoveTrainer and Stockfish are names and marks of their respective owners. We mention them only to say what ChessNotes works with or how it compares; ChessNotes uses none of their logos and is an independent project, not affiliated with, sponsored or endorsed by any of them.
7. Questions and source requests
For any question about these licences, or to request the source code of the software listed here, write to albanofrancesco22@libero.it. If you think we have used your work without the right credit, tell us and we will fix it promptly.