Chesss — Privacy Policy

Effective date: 28 September 2026

Chesss ("the app") helps you learn from your own chess games: it analyses them with a chess engine on your phone, explains why moves fail, and gives you drills and practice. This policy explains what the app does with information. Contact: privacy@kalnyx.in.

The short version

No account, email or phone number is needed. There are no ads and no analytics or tracking SDKs.
Your games, analysis and progress are stored on your phone and are not uploaded anywhere by this version of the app.
To import your games, the app asks Chess.com or Lichess for the public games of the username you type.

What the app handles, and where it goes

Information	Why	Where it goes
A Chess.com or Lichess username you type	To download your public games	Sent to Chess.com (`api.chess.com`) or Lichess (`lichess.org`) as part of the request; stored on your phone
Your public games from those sites	Analysis, drills, patterns	Downloaded to and stored on your phone only
Games you paste or share into the app, and games you play against the engine	Same	Stored on your phone only
Lichess login token (only if you choose "Log in with Lichess")	To read your own Lichess games	Stored on your phone, encrypted with a key held in the Android Keystore; sent only to Lichess
A name you type for a local profile	To label your games	Stored on your phone only
Settings and practice progress	Remembering your choices	Stored on your phone only
A diagnostic log of app errors and engine restarts	So you can report problems	Stored on your phone only; never sent automatically. Tokens are removed from it. You can view and copy it in Settings → Diagnostics

Chess.com and Lichess handle requests under their own privacy policies.

The app excludes its data from Android cloud backup and device-to-device transfer, so it stays on the phone it was created on.

Features that use the Chesss server

Some versions of the app may connect to a Chesss server for extra features. This version does not. If a future version does, these rules will apply, and this policy will be updated before it ships:

Explanations and server analysis send chess positions and moves (not your identity) to the server.
Screenshot and scoresheet import send the image you choose to the server for reading; images are processed and not kept.
Coach accounts are optional. If you join a coach with an invite code, a summary of your analysed games (counts, recurring patterns, positions of your own mistakes) and your username are shared with that coach until you choose Leave, which deletes them from the server.
All server traffic uses HTTPS.

Children

Chesss is not directed at children under 13 and does not knowingly collect personal information from them. The app has no chat, no social features and no ads.

Your choices and deletion

Delete everything: uninstall the app, or clear its storage in Android settings. All data lives on your phone.
Remove a Lichess login: Switch account in the app, or revoke the token at lichess.org → Preferences → Security.
Questions or requests: privacy@kalnyx.in.

Security

Account tokens are encrypted with the Android Keystore. Release builds only make HTTPS connections. Data is excluded from backups.

Changes

If this policy changes, the new version will be published at the same address with a new effective date before the change takes effect.