Stockfish.js 19.0.0, lite single-threaded WebAssembly build.
Copyright 2026 Chess.com, LLC, Nathan Rugg and the Stockfish contributors.
Distributed unmodified under GNU GPL version 3. See Copying.txt and AUTHORS.

Upstream: https://github.com/nmrugg/stockfish.js
Source revision: 54fde71d90c7c403964f6cacef48f7bbec495df1
Release: https://github.com/nmrugg/stockfish.js/releases/tag/v19.0.0

Corresponding source, build scripts and instructions: source.tar.gz (same directory).
Required lite network: nn-61e7af4bb97d.nnue (same directory).
Network source: https://tests.stockfishchess.org/api/nn/nn-61e7af4bb97d.nnue
Extract the source, place that network in src/, install Emscripten 3.1.7
(as specified in build.js), then run:
node build.js --lite --single-threaded --no-split
See README.md and build.js --help for additional build requirements.

This engine runs as a separate Web Worker using the standard UCI protocol.
The lite build prioritizes download size and differs in strength from the full engine.

Runtime SHA-256:
stockfish-19-lite-single.js d3344124ab067fb0b90ee77873bb8e9fbf5fc01bc525fe714b0f942581e889e6
stockfish-19-lite-single.wasm 57ac2d72312aba346760e3f173f687a8c211208e97a87268436f7f0e10bb5387