my·blunders is built to need as little of your data as possible. There are no accounts, nothing about you is stored on our servers, and everything you train on stays on your own device. This page explains exactly what that means.
Last updated: July 2026.
Public games only. You give a Lichess or Chess.com username — never a password. We only read games you have already made public on those sites, and we never sign in as you or act on your behalf.
No account, no personal details. We don't ask for your email, name, or any sign-up. A public username is the only thing you provide.
Nothing on our servers. Your games are fetched and handed straight back to you — we keep no copy. On the iOS app, your device talks to Lichess and Chess.com directly, with no server of ours in between. On the web, games pass through a thin stateless relay (browsers can't call those sites directly) that stores nothing.
Everything stays on your device. Imported games, generated puzzles, your progress, and your settings are saved only in your browser / the app (local storage). We can't see them. Clearing your browser data — or using the in-app “Clear all” — deletes them permanently.
Analysis runs on your device. The Stockfish engine that finds your blunders runs locally (in your browser on the web, in the app on iOS). Your moves are not sent anywhere to be analysed.
Lichess & Chess.com. To fetch your games we contact lichess.org and chess.com using the username you enter. Their handling of that request is governed by their own privacy policies.
No analytics, ads, or tracking. We don't use analytics SDKs, advertising, or third-party trackers. Nothing follows you around, and we don't build a profile of you.
my·blunders collects no personal information from anyone, including children. It reads only the public game data tied to the username you provide.