Privacy policy

Last updated November 4, 2026

Your puzzles and progress stay on your phone. Chess Calculator has no account and sends no usage statistics. The one time it talks to a server is when you ask for a coach tip, and what it sends is the chess, not you.

Who we are

Chess Calculator is made by Synergy Tecnologia Ltda (CNPJ 51.033.169/0001-89), Rua Vicente Oropallo, 70, São Paulo, SP, 05351-025, Brazil. We are responsible for the data described here. For anything about privacy, write to luis@synergytec.com.br.

What stays on your phone

The puzzle packs ship inside the app. Your attempts, ratings, theme ratings, drill progress, daily target, settings and the level you told us at the start are stored only on your device. We can't see them, and we have no copy of them. There is no account to create.

Coach tips

When you ask for a coach tip after a failed puzzle, the app sends a request to a small server of ours. The request contains the puzzle (its position and solution), the move you played, the engine's refutation of it and the theme involved, plus an anonymous install identifier so the server can count your free tips and check Premium. It never contains your name, your email or anything you typed.

Our server forwards the chess part of the request, without the identifier, to Google's Gemini API, which writes the explanation. Google processes that text under its own terms. We keep a short log of each request saying whether it was free, Premium, refused or failed, without the identifier, for as long as needed to run the service and never longer than twelve months. The count of free tips used by an install is kept on our server against the anonymous identifier.

Premium

Premium is a subscription sold through the App Store or Google Play, which handle the payment under their own privacy policies; we never receive your card details. To know whether an install has Premium, the app and our server use RevenueCat, a subscription service, which receives the anonymous install identifier and the purchase information from the store. We receive standard sales reports from the stores.

No usage statistics

The app includes no analytics or crash-reporting software. Apart from coach tips and purchases, it sends nothing to anyone. If that ever changes, we'll update this page and say so in the app.

Device backup

If iCloud backup or Android backup is on for your phone, your phone may copy the app's data to your own Apple or Google account, so it comes back on a new phone. That copy is managed by Apple or Google under your account, and we can't read it. You control it in your phone's backup settings.

The mail list

On our website you can ask us to tell you when Chess Calculator opens on your phone. If you do, we keep your email address and which phone you chose, using PostHog in the United States, only to send you that email. We don't share or sell it. We delete it once we've told you, or whenever you ask us to. This is separate from the app, which never sends your email.

Permissions

• Internet: for coach tips and purchases. Everything else works offline.
• Notifications: only if you turn on a daily training reminder. Reminders are scheduled on your phone; nothing is sent.

Security

Your data is kept in the app's private storage, which other apps can't read, and requests are sent over an encrypted connection. No method is perfectly secure, so keep your phone's screen lock on.

Deleting your data

Uninstalling Chess Calculator deletes everything it stored on your phone. To remove a device backup too, delete it from your Apple or Google account's backup settings. Because our server only holds an anonymous identifier, we normally can't find yours, but if you send us a request we'll help however we can.

Your rights

Depending on where you live, including under Brazil's LGPD and the EU's GDPR, you may have the right to access, correct or delete your personal data, to object to its use, and to complain to your data protection authority. Write to us to use these rights. Coach-tip requests are processed to provide the feature you asked for; the free-tip count is based on our legitimate interest in running the service fairly.

Children

Chess Calculator isn't directed at children under 13, and we don't knowingly collect data from them.

Changes

If we change this policy, we'll update this page and its date. If a change matters to how your data is used, we'll say so in the app or in the store listing.