Matkii uses Stockfish.js 19.0.1, Stockfish 19 Lite single-threaded (unmodified).
Copyright 2026 Chess.com, LLC and Stockfish contributors.
License: GNU GPL version 3. Full license: ./COPYING.txt

Corresponding source code, build scripts and build instructions (free access):
https://github.com/nmrugg/stockfish.js/tree/0d5dd7944f88c817c07a26bc4fb1905d5f9c46d6
Download corresponding source:
https://github.com/nmrugg/stockfish.js/archive/0d5dd7944f88c817c07a26bc4fb1905d5f9c46d6.tar.gz
Release: https://github.com/nmrugg/stockfish.js/releases/tag/v19.0.1
Build: Emscripten 6.0.9, node build.js --single-threaded --lite
See the upstream README and build.js for network weights and complete instructions.

The JavaScript and WASM files were extracted unchanged from stockfish@19.0.1
on npm. Matkii communicates with this separate engine using UCI postMessage.
The engine is downloaded only on the chess page and runs on the user's device.
The Lite build uses a small neural network; its strength differs from full Stockfish.
The interface does not claim a calibrated human or FIDE Elo for its three levels.

SHA-256:
stockfish-19-lite-single.js
ccb130d7ff29408531c47d859a49f91d59d4f482d05a53eb1a3231a4f624c91a
stockfish-19-lite-single.wasm
ee4f115bdb2d32cadf96cada104a05b5ec257d7ad6f57582190b49bc71f096de

npm tarball integrity:
sha512-bTwsO4e9HAwPBKls1+szcfibmaWRNzTF20rQE/XPdB3LOSoT6XTZDr1zYwriwSRRFT5MkvqrglPmJrKEVXGnyQ==