Privacy Policy
This policy explains what happens to your data when you use Chessby (formerly ChessBook), the chess app for iPhone and iPad. The short version: your chess data stays on your device and in your own iCloud Drive. We do not run a server, we have no user accounts, and we do not use analytics, advertising or tracking.
Who we are
Chessby is developed by Maksym Butsykin (“we”, “us”), who is responsible for this app and this policy. Contact: mbutsykin@gmail.com.
What we do not collect
- We have no server of our own. Nothing you do in the app is sent to us.
- No analytics, crash reporting or usage tracking.
- No advertising, and no advertising identifier (IDFA). The app does not ask for tracking permission because it does not track you.
- No location, contacts, photos, microphone or camera.
- No sign-up: there is no Chessby account.
Data the app keeps on your device and in your iCloud
Your books and games
Your books (PGN games, comments, opening repertoire, study progress, and games imported from Lichess or Chess.com) are stored as files:
- with iCloud sync on (the default when iCloud Drive is available), in the app’s folder in your iCloud Drive, so they appear on your other devices and in the Files app;
- with iCloud sync off (Settings › Storage), or without iCloud, only on your device.
iCloud is provided by Apple under your Apple Account. We cannot see or access your iCloud data.
On-device only
- A search index of your games (a database the app rebuilds from your books).
- Settings, including the names you enter as “my names” and the usernames of accounts you connect.
- Your Lichess sign-in token, kept in the iOS Keychain.
Chess engine
Analysis and game review use the Stockfish engine, which runs entirely on your device. Positions are not sent anywhere for analysis.
Third-party services
The app talks to the services below only for the features that need them. Each receives only what is listed, and handles it under its own privacy policy. Like any internet request, these requests reveal your device’s IP address to the service.
Apple (iCloud Drive, App Store)
Book files sync through iCloud Drive in your Apple Account. Purchases and subscriptions are processed by the App Store; we never receive your payment details. Apple Privacy Policy.
RevenueCat (subscriptions)
We use RevenueCat to manage Chessby Pro subscriptions: it checks your App Store receipts and tells the app whether Pro is active. RevenueCat receives your purchase and subscription history together with an anonymous, randomly generated customer ID. We do not send it your name, email or any chess data. We see anonymous purchase records in RevenueCat’s dashboard, which we use to provide your subscription and to understand how many people subscribe. RevenueCat Privacy Policy.
Lichess (optional)
If you connect a Lichess account, you sign in on lichess.org in a system browser sheet; the app never sees your password. Lichess gives the app a token with no extra permissions, which the app uses to read your username, download your games, and query the Lichess opening explorer (explorer.lichess.org) with the positions you look at in the Explore panel. Downloading games by username also works for players you look up. When you disconnect, the app asks Lichess to revoke the token and deletes it. Lichess Privacy Policy.
Chess.com (optional)
If you connect a Chess.com username, the app downloads that player’s public games and statistics from the Chess.com public API. Chess.com receives the username being looked up; no password or sign-in is involved. Chess.com Privacy Policy.
Files you open, share or copy
Importing a PGN file, sharing a game or book, and copying to the clipboard happen only when you choose to, through standard iOS controls. Where a shared file goes is up to you.
Keeping and deleting your data
- Books: delete them in the app or in the Files app. To remove everything Chessby keeps in iCloud, go to iOS Settings › your name › iCloud › Manage Account Storage (or Manage Storage) › Chessby and delete its data.
- On-device data: deleting the app removes its local data, settings and index.
- Lichess: use Disconnect in Settings › Lichess. You can also revoke Chessby’s access at any time on lichess.org in your account’s security / OAuth settings. Data Lichess holds about you is governed by Lichess.
- Chess.com: use Disconnect in Settings › Chess.com. Games you already imported stay in your books until you delete them.
- Subscription records: RevenueCat keeps anonymous purchase records as needed to provide and account for subscriptions. Because they are not tied to your identity, we may be unable to find a specific record; contact us and we will do what we can.
Your rights
Depending on where you live (for example under the GDPR or CCPA), you may have the right to access, correct or delete personal data and to object to its processing. Since we hold no personal data on our own systems, most requests are fulfilled by the controls above. For anything else, write to mbutsykin@gmail.com. We do not sell or share personal data.
Children
Chessby is a general-audience app and is not directed at children under 13. It does not knowingly collect personal information from anyone, including children.
Changes
If the app starts handling data differently, we will update this page and its effective date before the change ships. Significant changes will also be mentioned in the App Store release notes.
Contact
Maksym Butsykin · mbutsykin@gmail.com