Simple Chess Video Analyzer Extension

Watching a chess video and wondering what the engine thinks? Simple Chess Video Analyzer reads the board straight from the video and shows Stockfish's analysis next to it, live, as the game plays out. The extension is free and open source, with no ads or account needed.

HOW IT WORKS

1. Open a chess video (YouTube, Twitch, or any site with a video player).
2. Click the extension icon (or press Alt+Shift+A).
3. Drag a box around the board. That's it — analysis starts with the next move.

FEATURES

• Live evaluation bar and Stockfish's top 3 lines, updated as moves are played
• Best-move arrows drawn right on top of the video
• Chess.com-style move labels: Brilliant, Great, Best, Excellent, Good, Inaccuracy, Mistake, Miss and Blunder
• Tracks the whole game: side to move, castling rights, en passant and move history
• Ignores pieces the streamer picks up or hovers — the position only updates when a move is actually played
• Not fooled by arrows, circles or square highlights drawn on the board
• Works with any board colors and piece styles, and either side at the bottom
• Copy the position as FEN or open it on Lichess with one click
• Adjustable scan rate, up to every frame of the video

PRIVATE BY DESIGN Everything runs locally in your browser: the board recognition and the Stockfish engine. No account, no tracking, and nothing is ever uploaded.

FAIR PLAY The extension is for watching videos, not playing. It is switched off on chess playing sites such as chess.com and lichess.org.

FREE AND OPEN SOURCE Licensed under GPL-3.0. Source code: github.com/kawgit/Simple-Chess-Video-Analyzer-Extension

Not affiliated with or endorsed by Chess.com, Lichess, YouTube or any content creator.