Stockfish

Stockfish is a free and open-source chess engine, available for various desktop and mobile platforms. It can be used in chess software through the Universal Chess Interface.

Stockfish has consistently ranked first or near the top of most chess-engine rating lists and, as of October 2022, is the strongest CPU chess engine in the world. It has won the Top Chess Engine Championship 12 times and the Chess.com Computer Chess Championship 19 times.