ChessGuard — Cheat Detector

About

ChessGuard analyzes chess games and detects suspicious engine-assisted play using real engine evaluations from the Lichess Cloud Eval API.

HOW IT WORKS
─────────────
• Open any game on chess.com or lichess.org
• Click the ChessGuard icon — it automatically extracts the PGN and player ratings
• Click Analyze and get a full suspicion report in under 60 seconds

WHAT IT ANALYZES
─────────────────
• Average Centipawn Loss (ACPL) vs ELO-expected
• Best-move match rate vs statistical expectation
• Accuracy gap above ELO baseline
• Blunder/mistake/inaccuracy counts

SUSPICION SCORING
──────────────────
Every player gets a suspicion score from 0–100, calibrated against their ELO rating. A 300-rated player playing like a grandmaster is far more suspicious than a 2000-rated player doing the same. The verdict ranges from LIKELY CLEAN to SOMEWHAT SUSPICIOUS to HIGHLY SUSPICIOUS to HACKER.

FEATURES
─────────
• Auto-detects games on chess.com and lichess.org
• Works on live games, game review pages, and game history
• Paste any PGN manually or fetch by URL
• ELO-adjusted analysis — fair for all skill levels
• No account required

FREE & PRO
───────────
Free: 5 game analyses per day
Pro: Unlimited analyses ($3/month)

No data is collected. All analysis happens locally and via the Lichess public API.