Privacy Policy
Last updated: June 20, 2026
This Privacy Policy explains how the ChessImprover mobile app ("the app", "we", "us") handles information. ChessImprover is an independent, free chess-training app. By using the app you agree to this policy.
The short version:
• The app works offline and does not require an account or any sign-in.
• Your chess data (repertoires, played games, puzzle progress, settings) is stored only on your device — we never receive it.
• We collect anonymous crash reports and usage analytics through Google Firebase to find bugs and improve the app.
• No ads, no advertising identifiers, and we do not sell your data.
1. Information stored only on your device
The following stay on your device and are not transmitted to us:
- Your opening repertoires, imported lines, and folders
- Games you play against the engine and their reviews
- Puzzle progress, ratings, and streaks
- App settings (themes, sound, notification preferences)
Uninstalling the app removes this data from your device.
2. Crash and performance data
We use Firebase Crashlytics (a Google service) to receive automatic reports when the app crashes or becomes unresponsive. These reports help us fix problems and may include:
- The type of crash and a stack trace (including native engine crash diagnostics)
- Device model, operating-system version, and app version
- Device state at the time of the crash (e.g. memory/storage status) and a random installation identifier
Crash reports do not contain your name or contact details.
3. Usage and analytics data
We use Firebase Analytics (a Google service) to understand how the app is used in aggregate so we can improve it. This may include:
- A random app-instance identifier
- Device and operating-system information
- In-app events, such as which screens and features are used
- An approximate, coarse location derived from your IP address (e.g. country/region)
We do not collect the device advertising ID, and the app contains no advertising.
4. Network requests to Lichess
When you explore openings on the analysis board and a position is not already covered by the app's bundled opening data, the app may request opening statistics from the public Lichess Opening Explorer API. This sends only the chess position being viewed (in standard FEN notation) — no personal information. This does not happen during normal play or for common openings. Lichess's handling of such requests is governed by its own privacy policy.
5. What we do not collect
- No account, name, email address, or password (the app has no sign-in)
- No contacts, photos, microphone, or precise GPS location
- No advertising identifiers, and no third-party advertising
- We do not sell or rent personal information to anyone
6. How we use the data
Crash and analytics data are used solely to diagnose problems, improve stability, and guide which features to develop. We do not use it to identify you personally or to target advertising.
7. Service providers
We use Google Firebase (Crashlytics and Analytics) as a data processor. Data collected through these services is processed by Google in accordance with the Firebase Privacy and Security terms and the Google Privacy Policy, and may be processed on servers located in the United States or other countries.
8. Data retention
Crash reports and analytics data are retained according to Firebase's standard retention periods (for example, Crashlytics retains crash data for approximately 90 days). On-device data persists until you delete it or uninstall the app.
9. Children's privacy
ChessImprover is suitable for a general audience and is not directed at children under 13. We do not knowingly collect personal information from children. If you believe a child has provided us information, contact us and we will address it.
10. Your choices
Because the app uses no account, the simplest way to stop all data collection is to uninstall the app. You can also manage app permissions (such as notifications) and reset device-level identifiers through your device settings.
11. Changes to this policy
We may update this policy as the app evolves. Material changes will be reflected here with a new "Last updated" date.
12. Contact
Questions about this policy: chessimproverapp@gmail.com.