Credits pay for questions to the AI coach. They never expire.
PlayStockfish.com is a free online chess site built and maintained by Edgeway Software, a small independent software studio. The site launched in 2026 with a simple goal: let anyone play against the world's strongest chess engine in their browser, with nothing to download and nothing to install.
What began as a single board against Stockfish has grown into a set of tools for actually getting better — a coach that grades your moves as you play, a full review for games you have already finished elsewhere, a rating estimator, puzzles, and a collection of the great games of chess history.
The engine runs on your machine, not ours. Stockfish is compiled to WebAssembly and loaded straight into your browser, so it thinks locally, your games are never uploaded, and there is no queue, no daily limit and no cost to us in giving it away.
Face the engine at any strength, from gentle beginner bots to full grandmaster force.
Our own engine, written entirely through AI prompts. You set how deep it thinks.
Play a game while a second Stockfish at maximum skill grades every move you make.
Import a game by your Chess.com or Lichess username, or paste a PGN, and get the blunders, missed wins and accuracy scores — then practise what you got wrong.
Three games against calibrated opposition, and an honest estimate of your rating.
Watch large language models play each other at the board, or take one on yourself.
Mate in two and upwards, for the pattern recognition that wins games.
Replay the classics move by move, with annotations and notes on the players.
Most of PlayStockfish is open to anyone with no account at all. Some features do ask you to be signed in, and a free account takes under a minute to set up.
A few features run on credits. Every new account starts with some, and more can be bought in packs if you need them.
Questions, corrections, or feedback are always welcome via our contact page.
The site runs the unmodified Stockfish 18 engine, compiled to JavaScript and WebAssembly so it plays and analyses entirely inside your browser. It is one of the strongest chess engines in the world, and because it is open source, anyone can use it and learn from it.
Our own engine, and an experiment as much as an opponent: every line of it was written through AI prompts rather than by hand. It is nowhere near Stockfish's strength, which is rather the point — it plays a more human-feeling game, and you can set exactly how far ahead it looks.
The original Stockfish chess engine (GPLv3)
github.com/official-stockfish/StockfishThe JavaScript and WebAssembly port that lets the engine run in a browser
github.com/nmrugg/stockfish.jsHandles the rules on every board here: move generation, legality and PGN
github.com/jhlywa/chess.js