Open Source Notices

Last updated: May 29, 2026

Grandmaster Journey includes open-source software. This page lists components that require attribution or license notices under their terms.

Stockfish chess engine

This app uses the open-source Stockfish chess engine (bundled as stockfish-lite-js, Stockfish.js 18) to power evaluations, computer opponents in daily challenges, and related analysis features. Stockfish is copyright its respective authors and licensed under the GNU General Public License v3 (GPLv3).

The engine runs in an isolated WebView and communicates with the app only through standard UCI text commands. The app's proprietary UI and server code are separate from the engine binary.

Chess piece artwork

Optional chess piece artwork is adapted from themes published in the Lichess open-source project. Each set is © its respective author; license terms are listed in Lichess's copying file. Grandmaster Journey is not affiliated with Lichess.

• Stockfish.js source (engine build used in this app)https://github.com/nmrugg/stockfish.js
• Upstream Stockfish projecthttps://github.com/official-stockfish/Stockfish
• GNU General Public License v3.0https://www.gnu.org/licenses/gpl-3.0.html
• Lichess piece set licenses (COPYING.md)https://github.com/lichess-org/lila/blob/master/COPYING.md

Grandmaster Journey is an independent application and is not endorsed by or affiliated with the official Stockfish development team or Chess.com.

If we add other open-source components that require notices, we will list them here.