Star Math privacy

Last updated: 7 July 2026.

The short version

Your birth data stays on your phone. There are no accounts, no ads and no trackers. We keep anonymous tap counters, and if you send feedback we store the note you wrote.

What stays on your device

Charts you save (names, birth dates, times, places) live in your browser's local storage on your device, and so do any date-checks you save in the "Check a date" card (who the check is for, the activity, the date and the place: the question, not the answer). We never upload or store them on a server. Deleting a person in the app, or clearing the site's data, removes them. Because we hold no copy, that removal is permanent and we cannot restore it for you: use the backup button if you want to be able to get them back.

What leaves your device

• When you ask the question box something, your question is sent to our server and passed to Anthropic's Claude API to write the answer, along with the current planet positions shown on your screen. Anthropic does not use API data to train models.
• If your question names a person you saved, that person's computed chart positions are included so the answer can use them. This happens only when you ask about them.
• If you share a chart with the share button, the chart data is encoded in the link itself. It goes to whoever you send the link to, not to us. The same goes for the Share image: if a saved chart is open on the dial, the picture includes that person's name and birth date, visibly, as part of what you chose to send.
• If you back up your charts, the backup file contains every saved person's name, birth date, time and place in plain readable text, plus your saved date-checks. It is written by your device and goes wherever you send it: your downloads folder, your cloud drive, an email to yourself. It never comes to us. Treat that file the way you would treat the birth details themselves.
• If you use the feedback box, we store what you typed (or a voice note, if you record one), the contact you optionally gave, your browser's user-agent string, the time, and a snapshot of what the app was showing (the dial's date, the zodiac mode, your last question and its answer, any page errors). The snapshot never includes your saved charts. It all sits in our private storage so we can reproduce what you saw and fix it. Send feedback to the contact below to have yours deleted.
• If you turn on the daily notification, we store your browser's anonymous push address and your timezone (so the note arrives in your morning, not ours). Never your charts: the notification text is written by your own device from data that stays on it. Turning the nudge off deletes the stored address.

What we log

If the app hits an error, it automatically reports the error message and the technical state (the dial's date, the zodiac mode, page errors, screen size) so we can fix crashes nobody told us about. This automatic report never includes your saved charts or your chat text.

Standard web server logs (Cloudflare) with IP addresses and request paths, kept briefly for security. We also count anonymous usage events, for example "tour started" or "question not understood". These are bare counters with no identifiers, no cookies, no IP addresses and none of your text. For rate-limiting, a one-way hash of your IP is kept for a day; the raw address is never stored by the app. They exist so we can fix confusing parts of the app.

Data deletion

Your saved charts never leave your device, so you delete those yourself: remove a person in the app, or clear this site's data (or uninstall the app). To have anything you sent us deleted, a feedback note, a voice note, the optional contact you gave, and the app snapshot attached to it, email [email protected] and we will remove it. Chat questions are not stored beyond that. There are no accounts to delete.

Contact

Questions or data-deletion requests: [email protected]