About

The chess engine

When you play the computer or open the analysis board, the moves and evaluations come from Stockfish 18, running entirely in your browser. Nothing you analyse leaves your device.

What runs, exactly

• The official Stockfish 18 source, compiled to WebAssembly by the stockfish.js project and published as the npm package [email protected]. We use the single-threaded "lite" build, unmodified, so it runs on phones without special headers.
• The engine is a separate program in a Web Worker. This site talks to it over the standard UCI text protocol and never links against it.
• The 7 MB engine binary is downloaded once, on demand, from unpkg.com (with this site as a fallback), and its SHA-256 digest is checked against the one recorded here before it runs.

Licence

Stockfish is free software under the GNU General Public License, version 3. Copyright the Stockfish developers (see AUTHORS). You may download the exact files this site serves — the engine binary and the worker script — and their source at the links above. The rest of QED Night is a separate work and is not covered by that licence.

Binary digest (SHA-256): a8fbc05ec6920b56d7485826dcb02c5ffd2826bcbf751cf973046f237a9096f1