ChessGuard — Cheat Detector

Detect chess cheaters instantly. Paste a game URL or PGN and get an ELO-adjusted engine analysis with a suspicion score.

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.