Privacy Policy
Our Philosophy
Your fitness data belongs to you. Zestimer keeps your workouts on your device, sends as little as it can when a feature has to go online, and never sells your data or uses it for advertising. This page lists everything that leaves your device, and why.
What Stays on Your Device
Workout data: Your workout routines, history, and settings are stored locally on your device. If you use iCloud, your data is synced across your devices using your private iCloud account. This data is encrypted by Apple and remains inaccessible to us.
Health data: If you grant permission, Zestimer reads and writes data to the Apple Health app (HealthKit). This integration happens entirely on-device. Your health metrics stay within the Apple Health ecosystem and are never transmitted to Zestimer.
When a Feature Goes Online
Some features need a server. They go through ours, which runs on Cloudflare. It passes each request on and keeps no copy of what you send. Cloudflare’s request logs record the address each request went to (the words of a video search, for example); we use them only to fix errors, and they are deleted within a week.
Video and AI workouts: When you convert a video or ask for a workout, the text you type, the link you paste, or the file you choose is sent to Google’s Gemini API to build the workout, and the result comes straight back to your device. A clip from TikTok or a similar app is downloaded by your device from where it was posted, then sent on as a file.
Zest Points: AI features are paid for in Zest Points. To keep your balance, our server recognizes your copy of the app by the app transaction ID Apple issues for your Apple ID — Apple signs it, and it carries no name or email. Under that ID we keep your balance, the Zest Packs you have bought, when the app last connected and with which plan, country and app version, and a record of each AI request: when it was made, what kind it was (a chat or a video), what it cost, your plan, and the country it came from. The record never includes what you typed, the link, or the video. We use it to charge the right balance, to help when a purchase goes wrong, and to see what the AI costs. Contact us and we will delete it.
Video search: Searching for videos in the app sends your search words to the YouTube Data API.
Anonymous ID: The app also signs in to Firebase anonymously and gets a random ID with no name or email attached. Our server counts how many times each ID uses a feature in a day, as a guard against abuse, and those counts expire on their own. Firebase App Check confirms that requests come from the genuine Zestimer app.
Usage Statistics
The app records a handful of events — opening the app, finishing onboarding, starting, finishing or leaving a workout, seeing the Pro screen, and buying — with a few coarse labels such as days since install and whether you subscribe. They go to Google Analytics for Firebase under a random app ID, along with the basic device information Firebase collects automatically, such as device model, OS version, and country. They carry no name, email, or workout content, and are never used for advertising. They tell us whether people come back and finish what they start.
Subscriptions
Purchases are made and managed by Apple. We use RevenueCat to count subscriptions: it receives your Zestimer purchases from Apple under the same app transaction ID, never your name, email, or payment details.
The Wish Pool
Voting or sending a wish at zestimer.com/wishes needs Sign in with Apple. Apple gives us only a random identifier — we never ask for your name or email. We keep your votes, what you write and its language, and a sign-in cookie on api.zestimer.com. Only our team reads your wishes, and they appear to others only after we have rewritten and approved them. “Delete account” on that page erases your votes and everything you sent.
Services We Rely On
Each of these handles only the part described above:
- Apple — iCloud, Apple Health, App Store purchases, and Sign in with Apple
- Google — Firebase (anonymous ID, App Check, usage statistics), the Gemini API, and the YouTube Data API
- Cloudflare — hosts our server, this website, the Wish Pool, and your Zest Points balance
- RevenueCat — subscription statistics
- Spotify — only if you connect it to control your music; the connection is between the app and Spotify
No Ads, No Selling
Zestimer shows no ads, contains no advertising SDKs, doesn’t track you across other apps or websites, and never sells or rents your data.
Data Security
Your workouts are protected by Apple’s device security and iCloud encryption, and everything the app and this website send travels over encrypted connections. We recommend keeping iOS and watchOS up to date.
Changes to This Policy
When the way we handle data changes, we update this page and the date at the top.
Contact Us
If you have any questions about your data, or want something deleted, contact us at [email protected].