What is Stockfish used for?

Stockfish is a free, open-source UCI chess engine that analyzes positions and computes moves, used through a separate chess GUI. It is a good fit for analyzing chess games and engine for chess analysis software.

Is Stockfish open source?

Yes. Stockfish is open source under the GPL-3.0 licence. Its source code is on GitHub at official-stockfish/Stockfish and is written mainly in C++.

Yes. Stockfish is open source, so the software itself is free to use.

Can I self-host Stockfish?

Yes. Stockfish can be self-hosted on your own server or infrastructure; there is no official hosted version.

What are some alternatives to Stockfish?

Similar open-source tools in the Games & Emulation category include Sunshine, RPCS3 and Lichess. SaaS products in the same category include Chess.com, Chess It Up and ChessCopilot.

Is Stockfish actively maintained?

Yes. The most recent commit to Stockfish was on 30 September 2026. The project has 17k stars on GitHub.

Stockfish: open-source games & emulation

About Stockfish

Stockfish is a free UCI chess engine, derived from Glaurung 2.1, that analyzes chess positions and computes the best moves it can find. It is an engine only: it has no graphical interface for showing a board or entering moves, so it is used through separate chess GUIs that speak the UCI protocol.

The distribution includes the full C++ source with a Makefile for Unix-like systems, a license text, an authors list and a network file with the .nnue extension that holds the neural network used for NNUE evaluation. Binary distributions have that network embedded. Documentation on the project site covers usage with different GUIs.

Stockfish is released under the GPL-3.0 license. Improvements are tested through a distributed testing framework called Fishtest, and the project accepts donated hardware as well as code contributions. Community discussion happens on GitHub and Discord.

Key features

UCI chess engine for use with GUIs
NNUE neural network evaluation
Position analysis and move computation
C++ source with a Unix Makefile
Distributed testing through Fishtest
Binary builds with embedded network

Good fit for

→Analyzing chess games
→Engine for chess analysis software

Built with: C++
Tags: chess; chess-engine; uci; nnue; cpp; analysis; gpl; game-ai

Stockfish: questions and answers

What is Stockfish used for?: Stockfish is a free, open-source UCI chess engine that analyzes positions and computes moves, used through a separate chess GUI. It is a good fit for analyzing chess games and engine for chess analysis software.
Is Stockfish open source?: Yes. Stockfish is open source under the GPL-3.0 licence. Its source code is on GitHub at official-stockfish/Stockfish and is written mainly in C++.
Is Stockfish free?: Yes. Stockfish is open source, so the software itself is free to use.
Can I self-host Stockfish?: Yes. Stockfish can be self-hosted on your own server or infrastructure; there is no official hosted version.
What are some alternatives to Stockfish?: Similar open-source tools in the Games & Emulation category include Sunshine, RPCS3 and Lichess. SaaS products in the same category include Chess.com, Chess It Up and ChessCopilot.
Is Stockfish actively maintained?: Yes. The most recent commit to Stockfish was on 30 September 2026. The project has 17k stars on GitHub.