KesPrep checks hundreds of your Chess.com games with Stockfish, finds the mistakes you repeat, and teaches you from your own games.
Chess.com reviews one game at a time. KesPrep looks across all of them.
Mistakes grouped by opening, phase of the game, time left on the clock and colour. You see patterns, not single errors.
The five games that best show your main weakness, so you know which games to study first.
The game stops at the critical moments and asks for your move before it shows the Stockfish line.
SoonPositions from your own blunders, with the best move. You practise the exact mistakes you make.
SoonWhere a low clock causes your errors, with numbers.
Where you lose your advantage in each opening, and won endgames you failed to win, to replay against Stockfish.
SoonBlunders per game with less than 30 seconds on the clock (0.9), against all other games (0.2).
Every move is judged by the open-source engine Stockfish. The AI never judges a move. It only turns Stockfish's numbers into plain language, so every lesson rests on facts from your games.
Type your Chess.com name and how many games to check. Nothing to install.
A progress bar shows how far it is and how long is left. Games that were checked before are never checked twice.
See your main weaknesses first, then work through key games and puzzles made from your own mistakes.
Accounts, saved history and higher limits are coming. Until then, everything here is free to try with just a Chess.com username.
Plans and prices will be announced on this page before anything is charged. Until then, everything on this page is free to use, capped at a generous daily limit per visitor.
We're not lawyers. This is written in plain English on purpose, and it will get a proper legal pass before KesPrep leaves early access.
What we collect. The Chess.com username you type in, and the public game data Chess.com's own API returns for it (moves, results, time controls, dates). We don't ask for your name, email or password, because there's no account yet.
What we don't collect. No payment details -- there's nothing to pay for yet. No location, device fingerprinting, or third-party ad trackers.
How it's used. Your games are run through a chess engine on our server to find patterns in your mistakes, and that report is shown back to you. We don't sell, share, or use it to train anything beyond your own report.
How it's stored. Analyzed games and the resulting report sit in our server's database, tied only to the username you entered, so that re-analyzing the same account later is fast instead of starting from zero. A couple of small, local-only preferences (like your weekly-plan checkboxes) live in your browser's storage, not on our server.
Who else sees it. Nobody. The only outside call we make with your username is the one Chess.com's own public API requires to fetch your public game history.
Deleting your data. Signed in, click "Delete account" to remove your account immediately, yourself. Analyzing without signing in, email privacy@kesprep.dev with the username to delete, and we'll remove its stored games and report.
Signing in. Signing in with Google is optional and only saves your Chess.com username so you don't retype it -- we get your email and name from Google, nothing else, and we don't post or share anything on your behalf.
Rate limiting. We log how many games your IP address has had analyzed each day, purely to keep the free tier usable for everyone. That log doesn't leave the server and isn't linked to anything else about you.
KesPrep is provided free, during early access, as-is and without warranty -- we're a small, independent project, not a company with an SLA. The coaching advice it gives is generated from engine analysis and templated summaries, not a human coach or licensed instructor; use your own judgment, especially before relying on it to prepare for something that matters.
Only analyze accounts you own or have the owner's permission to analyze. Don't use KesPrep to scrape, bulk-harvest, or otherwise abuse Chess.com's public API beyond what a normal visitor's use of this site requires -- that's also a condition of Chess.com letting any of this work.
Daily analysis limits exist to keep the service free for everyone and may change without notice. We may change, pause, or discontinue any part of the service, including during early access, and will try to give notice on this page when a change affects stored data.
These terms may be updated as the product grows past early access (accounts, payment, etc.); material changes will be noted on this page.
Other third-party parts, such as piece sets, are listed in our third-party notices.
KesPrep is an independent project. It is not made, approved or endorsed by Chess.com or by the Stockfish team. It uses the public Chess.com data interface.