Cysmos Chess Coach Privacy Policy

Last updated: 2026-10-23 | App: Cysmos Chess Coach (app.cysmos.chesscoach) | Android

The short version

Cysmos Chess Coach works with nothing sent to us unless you turn on crash reporting and analytics in Settings → Account. Even then, what leaves your device is an event name and sometimes a small number, never a chess position, a move or anything you typed. Your games are played, reviewed and explained on your own device, on the free version and on Pro alike. You need no account to use the app.

1. What stays on your device

Your games, the positions you reach and the moves you play.
The Stockfish review and the AI explanations of it. The AI model runs on the phone itself; no game is sent to an AI service, to us or to anyone else for this.
Your drills, puzzle progress and settings.

If you choose to point the app at an Ollama-compatible server you run yourself (Settings → Engine & AI), review requests go from your device to that server and nowhere else.

To run the AI coach, the app downloads the model file once. That download is an ordinary file request: the server delivering it sees your IP address, as with any download, but no game data.

2. Crash reports and analytics (opt-in, off by default)

Crash reporting and analytics share one switch in Settings → Account. It is off on every install, in every country. Nothing is sent before you turn it on, and turning it off stops sending at once. Both are provided by Sentry.

Crash reports (release builds only): a stack trace, the app version, the device platform and the steps Sentry records before the crash. Before a report leaves the device, login parameters from Lichess (authorization codes and similar) and anything that looks like an API key are removed from it.
Analytics: a few product events, each sent at most once: app installed, first game started, first game finished, first review run, and Pro purchased. Each event is a name and at most a small number, nothing else. The app refuses to send anything that looks like a chess position, a move list or PGN text.

Crash reports and events are kept for the retention period of our Sentry project and then deleted automatically.

3. What is never collected

The moves you play, the positions you reach, or any PGN or FEN text.
What the coach says about your moves.
Anything you type into the app.

4. Lichess connection (optional)

You can connect a Lichess account to import your games and see your weaknesses across your history (Settings → Account → Lichess).

Read-only: the app asks Lichess for no permissions at all, so it can only read public information (your profile and public games). It cannot play moves, change settings or act on your account.
Stored on your device: the access token, in the Android Keystore, never in a plain settings file. Your Lichess username and your public ratings are kept in the app's ordinary settings.
What leaves the device: requests to lichess.org only, to fetch your profile and games. Imported games are stored and analysed on your device.
Disconnecting: "Disconnect" in Settings revokes the token at Lichess and deletes it from the device. Uninstalling the app only deletes the local copy; the token then stays valid at Lichess until it expires (about a year). Disconnect first if you want it revoked at once.

Lichess is a separate service with its own privacy policy.

5. Pro purchase (Google Play Billing)

Pro is a one-time in-app purchase made through Google Play Billing. Google processes the payment under its own terms and privacy policy; we never see your payment details. The app reads whether Pro is active from Google Play's purchase record on your device, so Pro also works offline. There is no subscription.

6. Google Play

The app and its Stockfish engine are delivered by Google Play. Google processes the data needed for installing and updating apps under its own privacy policy.

7. No advertising, no data sale

The app carries no advertising and no advertising SDK, and we do not sell or share any data for advertising or any other purpose.

8. Children

The app is not directed at children and does not knowingly collect personal information from children. It needs no account, and with crash reporting and analytics off (the default) it collects nothing that could identify anyone.

9. Your rights

Under the GDPR you have the right to access, correct and delete your data, to restrict or object to its processing, to data portability, and to withdraw your consent at any time (the switch in Settings). You can complain to the Austrian data protection authority (Datenschutzbehörde). The general part of our privacy notice, with the controller and hosting details, is at cysmos.com/datenschutz.

10. Changes to this policy

If what the app collects changes, this policy is updated before the change ships, not after.

11. Contact

For privacy questions or deletion requests: Email: hello@cysmos.email. We answer privacy requests within 30 days.