Free tool
Chess opening analyzer
An opening explorer tells you how the world scores in a line. This tells you how you score in it. Audit Chess turns your real games into an opening tree ranked by your own win/draw/loss at every branch, so the lines that quietly lose you rating stop hiding behind an okay overall record. Free, in your browser, no account.
Your results, not the database’s
Most opening tools rank moves by how a huge database of strangers performs. Useful for learning theory, useless for finding your leaks - because a line can be perfectly sound and still be your worst opening, simply because you never learned the middlegames it leads to. The opening tree is built from your games only, so every branch shows your real score and you can walk forward to the exact move where it collapses.
That collapse point is the highest-value thing to study: it is almost always the first position you reach without a plan. Fix that one move and the whole line starts scoring.
From “this opening loses” to a fix
Once the analyzer flags a weak opening, the rest of Audit Chess helps you do something about it: the blunders you make in that line become puzzles from your own games, and the weakness view ties the opening to the mistakes it produces. For the study method, read chess opening preparation and how to improve your opening.
Analyze your openings, or an opponent’s
The same tree works as a scouting tool. Point it at an opponent and you see the openings where they score worst, matched to your repertoire so you play lines you already know. Or widen out to a full game analysis to see how your openings connect to the rest of your play.
Curious where openings go wrong for everyone, not just you? Explore our opening trap tree - a database of common opening traps mined from master-level games - to see the tricks that catch players in the lines you play.
What is Audit Chess?
Audit Chess is a chess analysis platform that reads your Chess.com or Lichess game history and identifies the recurring weaknesses, opening tendencies, blunders, blown wins, missed mates and endgame patterns that are hard to see from a single game. It runs Stockfish in your browser, needs no account, and never uploads your games.
What makes it different: most chess engines analyze one position or one game. Audit Chess focuses on the patterns across your whole history - and turns them into training, so your own blunders become Stockfish-verified puzzles and your weakest openings become concrete things to study.
Frequently asked questions
How do I analyze my chess openings?+
Enter your Lichess or Chess.com username and Audit Chess builds an opening tree from your real games, ranked by your win/draw/loss record at every branch. You can walk move by move to see exactly where your results fall off - the point at which a line stops scoring for you - rather than guessing from opening theory.
How is this different from an opening explorer?+
A database explorer shows how millions of other players score in a line. That is theory. This analyzer shows how you score in it - your own results, move by move. A line can be objectively fine and still be a disaster for you because you do not know the resulting middlegames, and only your own games reveal that.
Does it tell me what to fix?+
Yes. Because every branch is tied to your results, the openings quietly costing you points rise to the top, and you can see the exact move where your score collapses. That is the move to study - usually the first position you reach without a plan.
Can I use it to prepare against an opponent?+
Yes. Point it at an opponent's username instead of your own and the same tree shows their weakest openings, so you can steer toward the lines where they score worst - matched to your own repertoire.
Audit Chess is free and not affiliated with Chess.com or Lichess.