chessray
See the best move and eval bar on any chess board on your screen.
A free, open-source Chrome extension. Streams, videos, replays, PDFs, screenshots — Stockfish's analysis painted on the board as it plays.
Features
Top-move arrows drawn on the board, color-coded by centipawn loss.
A live evaluation bar, updated as moves happen.
Updates when the board on screen changes.
Click an arrow to play through the engine's line.
Works on any site — streams, videos, PDFs, screenshots.
How it works
Captures pixels and recognizes the board with computer vision. No site integration.
Finds the highlighted squares to know the last move and whose turn it is.
Stockfish 18 runs on-device. No network calls — nothing leaves your machine.
Not for cheating
chessray is for watching and studying chess, not playing it.
It won't run on chess.com or lichess.org.
Open source
Free and open source under GPLv3. Built as a nonprofit project.
Read the code, file an issue, or contribute on GitHub.