1. Who we are
FastZen ("the app", "we") is an intermittent fasting tracker for iOS and Apple Watch. This policy explains what data the app handles and how Apple's services are involved.
2. Data stored on your device
FastZen stores the following data locally on your device using Apple's SwiftData and UserDefaults:
- Fasting sessions — start time, end time, plan type, and notes you add.
- Weight entries — values and dates you log.
- Hydration entries — water intake amounts and timestamps.
- App settings — preferences such as units, target plan, and notification choices.
This data stays on your device. We do not run a backend server, and we do not receive a copy of it.
3. Data shared between FastZen components
FastZen uses an Apple App Group (group.com.perrylee.fastzen) so the main app, the Apple Watch app, and the Home Screen / Watch widgets can read the same fasting data. This sharing happens entirely on your device or between your paired devices through Apple's frameworks.
4. Apple HealthKit
If you grant permission, FastZen can read and write the following HealthKit data types so your fasting tracker stays in sync with the Health app:
- Body Mass (weight)
- Height
- Dietary Water (hydration)
HealthKit access is optional. You can grant or revoke permissions at any time in Settings → Privacy & Security → Health → FastZen. We never see your HealthKit data — it is managed by iOS and stays on your device or in your iCloud, governed by Apple's privacy controls.
5. Notifications
If you enable notifications, FastZen schedules local reminders (e.g., "fast complete", "milestone reached") on your device using Apple's UserNotifications framework. These are local notifications — they are not sent through any server we operate.
6. Purchases (StoreKit)
In-app subscriptions and purchases are processed by Apple via StoreKit. FastZen verifies your subscription status using Apple's signed transaction records. We do not see your payment details, billing address, or Apple ID. For information about how Apple handles your purchase data, see Apple's Privacy Policy.
You can manage or cancel subscriptions any time in Settings → [Your Name] → Subscriptions on your iPhone.
7. Analytics and tracking
FastZen does not include third-party analytics, advertising SDKs, crash reporting services, or tracking pixels. We do not assign you an advertising identifier and we do not track your activity across other apps or websites.
8. Data we do not collect
- We do not require an account, email address, or phone number.
- We do not collect your contacts, photos (unless you choose to share a card), location, or microphone audio.
- We do not sell or share data with data brokers.
9. Your choices and control
- Delete your data: Uninstalling FastZen removes the app's local data from your device. Individual fasting, weight, and hydration entries can also be deleted from inside the app.
- HealthKit: Revoke read/write permissions in iOS Settings at any time.
- Notifications: Disable in iOS Settings or inside FastZen.
- Subscriptions: Manage through Apple's Subscriptions settings.
10. Children's privacy
FastZen is not directed to children under 13 (or the age of digital consent in your jurisdiction). We do not knowingly collect data from children.
11. Changes to this policy
If we make material changes, we'll update the "Last updated" date at the top of this page and, where appropriate, notify you in the app. Continued use of FastZen after a change means you accept the revised policy.
12. Contact
Questions about this policy? Email lpgreat@qq.com.