Stockfish Free Chess Engine

Stockfish is a free and open-source chess engine, available for various desktop and mobile platforms. It is developed by Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad, Stéphane Nicolet, Stefan Geschwentner, and Joost VandeVondele, with many contributions from a community of open-source developers.

Initial release November 2, 2008.

Website: stockfishchess.org

Stockfish is consistently ranked first or near the top of most chess-engine rating lists and is the strongest CPU chess engine in the world. It won the unofficial world computer chess championships in seasons 6 (2014), 9 (2016), 11 (2018), 12 (2018), 13 (2018), 14 (2019), 16 (2019), 18 (2020), 19 (2020), 20 (2020-21) and 21 (2021). It finished runner-up in seasons 5 (2013), 7 (2014), 8 (2015), 15 (2019) and 17 (2020).

Stockfish is derived from Glaurung, an open-source engine by Tord Romstad released in 2004.

Stockfish has been a very popular engine on various platforms. On desktop, it is the default chess engine bundled with the Internet Chess Club interface programs BlitzIn and Dasher.

On mobile, it has been bundled with the Stockfish app, SmallFish and Droidfish. Other Stockfish-compatible graphical user interfaces (GUIs) include Fritz, Arena, Stockfish for Mac, and PyChess.

Stockfish can be compiled to WebAssembly or JavaScript, allowing it to run in the browser. Both Chess.com and Lichess.org, the two most popular chess sites, provide Stockfish in this form in addition to a server-side program.