Engines are flawless, humans play FlawChess
Find and fix the flaws in your game. Free full-game analysis of every chess.com and lichess game: tactics, openings, endgames, and time management.
Your Best Practical Move
- The FlawChess Engine shows your best practical move, not just the objective one: every move is scored by how likely you are to find and execute it, including the follow-ups.
- Judged against a typical human opponent, not perfect defense: each move is scored against the replies a player at their level would realistically pick, so the practical best can differ from the Stockfish best.
- Tuned to your level: powered by Stockfish + Maia, with a “Play style” dial that shifts from human-realistic to engine-precise.
Your Best Practical Move
- The FlawChess Engine shows your best practical move, not just the objective one: every move is scored by how likely you are to find and execute it, including the follow-ups.
- Judged against a typical human opponent, not perfect defense: each move is scored against the replies a player at their level would realistically pick, so the practical best can differ from the Stockfish best.
- Tuned to your level: powered by Stockfish + Maia, with a “Play style” dial that shifts from human-realistic to engine-precise.
Game and Tactic Analysis
- Run Stockfish over your entire chess.com and lichess history.
- Understand, replay, and learn from your blunders: mistakes are tagged with the tactic behind them (fork, pin, skewer, and 20+ motifs).
- Track your blunder rate over time, and see how often you fall for each tactic versus your opponents.
- Discover gem moves: the only good move in a position that most players at your rating would miss.
- Filter your whole game history by tactic, depth, and severity.
Game and Tactic Analysis
- Run Stockfish over your entire chess.com and lichess history.
- Understand, replay, and learn from your blunders: mistakes are tagged with the tactic behind them (fork, pin, skewer, and 20+ motifs).
- Track your blunder rate over time, and see how often you fall for each tactic versus your opponents.
- Discover gem moves: the only good move in a position that most players at your rating would miss.
- Filter your whole game history by tactic, depth, and severity.
Personalized Puzzle Training
- Every puzzle is built from your own blunders, not a generic puzzle set.
- Is there only one good move, or several? Commit before you play. Quiet positions are mixed in, so there isn't always a tactic waiting.
- Spaced repetition brings each position back next session, then after three days, then ten, until you've solved it three times.
- Pick your training days and build a session streak.
Personalized Puzzle Training
- Every puzzle is built from your own blunders, not a generic puzzle set.
- Is there only one good move, or several? Commit before you play. Quiet positions are mixed in, so there isn't always a tactic waiting.
- Spaced repetition brings each position back next session, then after three days, then ten, until you've solved it three times.
- Pick your training days and build a session streak.
Human-like Bots
- Play against 24 named opponents driven by the FlawChess Engine: they blunder, overpress, and grind like real players, not like a computer with a handicap.
- Four playing styles (Attacker, Trickster, Grinder, Wall) across six rating rungs from 800 to 1800, each with its own opening book and personality.
- Every finished game lands in your library, ready for Stockfish, Maia, and FlawChess Engine analysis like any other game.
Human-like Bots
- Play against 24 named opponents driven by the FlawChess Engine: they blunder, overpress, and grind like real players, not like a computer with a handicap.
- Four playing styles (Attacker, Trickster, Grinder, Wall) across six rating rungs from 800 to 1800, each with its own opening book and personality.
- Every finished game lands in your library, ready for Stockfish, Maia, and FlawChess Engine analysis like any other game.
Opening Explorer & Insights
- Get a detailed statistical analysis for every move you’ve played.
- Compare your win/draw/loss rate to the Stockfish evaluation at the end of the opening.
- Scan the first 8 moves of all your games to surface opening strengths and weaknesses.
- Bookmark your favorite openings, compare their performance, and see how your opening study impacts your win rate over time.
- Scout your opponent's repertoire before a match.
Opening Explorer & Insights
- Get a detailed statistical analysis for every move you’ve played.
- Compare your win/draw/loss rate to the Stockfish evaluation at the end of the opening.
- Scan the first 8 moves of all your games to surface opening strengths and weaknesses.
- Bookmark your favorite openings, compare their performance, and see how your opening study impacts your win rate over time.
- Scout your opponent's repertoire before a match.
Endgame Analytics
- Measure how well you convert winning endgames and recover from losing ones.
- Track your Endgame ELO over time by platform and time control.
- Get personalized feedback on what your stats mean.
Endgame Analytics
- Measure how well you convert winning endgames and recover from losing ones.
- Track your Endgame ELO over time by platform and time control.
- Get personalized feedback on what your stats mean.
Time Management Stats
- See your average time advantage or deficit when entering the endgame.
- Find out if you crack under time pressure more than your opponents.
- Compare your flag rate to your opponents' per time control.
Time Management Stats
- See your average time advantage or deficit when entering the endgame.
- Find out if you crack under time pressure more than your opponents.
- Compare your flag rate to your opponents' per time control.
🏗️ Under active development. Bug reports and feature requests are welcome on GitHub or via [email protected].
Frequently asked questions
Acknowledgements
FlawChess is built with and inspired by these projects:
- Lichess — open-source chess platform and game data API
- Chess.com — chess platform and game data API
- OpeningTree.com — inspiration for position-based opening analysis
- ChessGoals — cross-platform rating comparison data
- python-chess — chess logic, move generation, and Zobrist hashing
- Stockfish — open-source chess engine for position evaluation
- Maia Chess — human-like neural model powering the move-probability predictions
- FastAPI — async Python web framework
- chess.js — chess move validation and game state
- react-chessboard — interactive chessboard component
- Recharts — composable chart library
Free to use. No credit card required.