Terms of use
Who may use Blunderbase
Blunderbase is for adults. You must be 18 or older to hold an account. There is no version of this service for children, and accounts are invitation only during the beta.
What Blunderbase does
You give Blunderbase a Chess.com username. Blunderbase reads that username’s completed Rapid and Blitz games from Chess.com’s public archive, analyses them with the Stockfish engine, and turns the mistakes it finds into review positions. You write a short reflection about a position, and Blunderbase shows you an explanation of what the engine already proved.
That archive is public, and Blunderbase does not sign in to Chess.com, so it cannot check that the username is yours. Give it your own account. Blunderbase follows one account: a username you enter later replaces the saved one, and the games already imported stay in your history.
Blunderbase reads completed games only. It never reads, shows, or analyses a game that is still being played, and it has no browser extension, overlay, or board integration of any kind.
Fair play
Do not use Blunderbase during a live game, anywhere. Everything here is about games that have already finished, and using an engine while you play breaks the rules of every chess site and teaches you nothing.
Blunderbase’s practice board plays against Stockfish locally and is never connected to a game on another site.
Your account and your data
Your games, analyses, reflections, and practice history are private to your account. Nobody else using Blunderbase can read them.
You can delete your account at any time. Deleting it deletes your imported games and everything derived from them. See the privacy notice for what is stored and for how long.
What Blunderbase does not promise
Blunderbase is a beta. It may be unavailable, it may lose a session, and its coaching may be wrong. Chess evidence comes from Stockfish and move legality from a chess library; the written explanations are generated and may be unclear even when the underlying evidence is correct. Do not treat anything here as a guarantee of improvement.
Blunderbase is provided as is, without warranty. Blunderbase is not liable for any loss arising from its use, to the extent the law allows.
Not affiliated with Chess.com
Blunderbase is an independent tool. It is not affiliated with, endorsed by, or sponsored by Chess.com, and Chess.com is not responsible for it. Your use of Chess.com remains governed by Chess.com’s own terms.
Ending your use
You may stop using Blunderbase and delete your account at any time. Blunderbase may close an account that is used to assist play during live games, or that is used in a way that breaks these terms.
Changes
If these terms change in a way that matters, you will be asked to read and accept the new version before you continue. The version you accepted is recorded with the date.
Contact
Write to johnny.barhouche@gmail.com.