Free · Anonymous · On-Device

Turn the game you just lost into next week's win.

Import a Chess.com, Lichess or PGN game. BlunderLoop analyzes it with Stockfish, finds the mistake pattern, and gives you a position to practice — free, with no signup required.

The full game stays on this device — nothing is uploaded.
Analyzed locally on your device with Stockfish WASM.
Runs on your device — a full game usually takes about a minute.
Position after 17...Qh4?-34% Win Chance
Coach mark: 17...Qh4? leaves queenside fork openBest: 17...Nf6
The BlunderLoop Method

How the loop cures repeated mistakes

Unlike one-off engine report cards, BlunderLoop follows the mistake until you fix it.

4-Step Loop
Continuous Mastery
01 IMPORT
Fetch real gamesConnect Chess.com, Lichess or paste PGN to analyze locally on your device.
02 FIND
Isolate turning pointStockfish extracts the single decision move that altered your winning chances.
03 PRACTICE
Solve the positionThe exact mistake becomes your next practice puzzle without engine crutches.
04 VERIFY
Confirm it’s fixedSpaced repetition re-tests the pattern in future games until verified.