Who we are
Chess Blundr (“we”, “us”) runs the website at chessblundr.com, a free tool for reviewing chess games. This policy explains what data the site uses, where it goes, and the choices you have. If you have a question about it, email hello@chessblundr.com.
What we don’t collect
- We don’t ask you to create an account, and we don’t collect your name, email address or password.
- We don’t run analytics, tracking pixels or advertising scripts.
- We don’t set cookies.
- We don’t sell or share personal data, because we don’t hold any.
How your games are analyzed
Game analysis runs entirely in your browser, using a copy of the Stockfish chess engine that is downloaded with the page. The games you load and the analysis of them are not uploaded to our servers.
When you upload or paste a PGN, the file is read in your browser and never leaves your device.
When you import games by username, your browser requests that player’s public games directly from the Chess.com or Lichess public API. That request goes from your browser to their servers, not through ours, and is covered by their privacy policies. Those services will see your IP address and the username you looked up.
What is stored on your device
The site saves a few things in your browser’s local storage so your progress is still there next time. This data stays on your device. We can’t see it, and it isn’t sent anywhere.
- Practice deck: puzzles made from your mistakes and when each one is next due.
- Mistake DNA stats: summaries of games you have analyzed, so they don’t need to be analyzed again.
- Saved reviews: engine evaluations for games you reviewed, so reopening them is instant.
- Lesson progress: which Learn lessons you have completed.
- Practice log: how many puzzles you solved each day, for your daily goal and streak.
- Your username: the Chess.com or Lichess username you last looked up, so new games can sync when you come back. You can turn this off on the Mistake DNA page.
- Preferences: your light or dark theme and whether move sounds are muted.
You can back up, restore or delete all of it on the Your data page, or by clearing this site’s data in your browser settings. Data saved on one browser or device isn’t available on another unless you move it there with a backup file.
Third-party services
- Hosting. Like any website, our hosting provider receives standard request information (such as IP address, browser type and the page requested) in order to serve the site, and may keep it briefly in server logs for security and reliability.
- Google Fonts. The site’s fonts load from Google Fonts, so your browser connects to Google’s servers when a page loads. See Google’s privacy policy.
- Chess.com and Lichess. Contacted only when you import games by username, as described above.
If you email us, we use your email address and message only to reply to you. We don’t add you to a mailing list. You can ask us to delete our correspondence with you at any time.
Children
Chess Blundr is suitable for players of all ages and does not knowingly collect personal information from anyone, including children under 13.
Your rights
Depending on where you live, laws such as the GDPR or CCPA give you rights to access, correct or delete personal data about you. Because the site keeps your data on your own device, you can exercise most of these rights directly by clearing your browser’s site data. For anything else, email us and we’ll help.
Changes to this policy
If we change how the site handles data, we will update this page and the date at the top. If we ever start collecting personal data, we will say so clearly here before it happens.