Privacy Policy
TennisLooker · Tennis tracker for Apple Watch
Effective date: October 2, 2026 · Developer: Weihao Chen (陈伟灏)
In short: TennisLooker does not collect, upload, sell or track any of your data. Your sessions, health data and settings stay on your own Apple Watch, iPhone and Apple Health. The app has no servers and no accounts.
1. Data the app uses
| Data | Why |
|---|---|
| Health data (read): heart rate, active energy, resting (basal) energy, steps, walking + running distance | Shows live heart rate and calories while you play and builds the session report (heart-rate zones, energy, distance). Read only after you start a session. |
| Health data (write): tennis workouts | Saves each tennis session to the Health app so it counts toward your fitness records. |
| Watch motion sensors (rotation, acceleration, arm orientation) | Detects swings, stroke types (forehand, backhand, serve…) and swing speed during sessions and stroke calibration. Raw sensor data is not saved unless you turn on “Developer → Record raw sensor data” yourself. |
| Profile you enter: racket hand, watch wrist, backhand style, age | Interprets swing direction and estimates your maximum heart rate and heart-rate zones. |
| Stroke calibration samples | Remembers what each of your strokes looks like so later swings can be recognized. |
| Session records: duration, swings, stroke types, speed, heart rate, calories, score | History, trends and share posters on iPhone. |
| Photos (add only, never read) | Requested only when you tap “Save to Photos” to save a share poster. The app never reads your photo library. |
2. Where data is stored
- Sessions, settings and calibration samples are stored in the app’s own storage on your Apple Watch and iPhone.
- Watch and iPhone sync directly through Apple’s Watch Connectivity, without any third-party server.
- Health data is stored and managed by Apple Health; the app reads or writes it only with your permission.
- Your iPhone backups (including iCloud Backup, if you turned it on) include the app’s local data according to your system settings. The app itself never uploads any data to iCloud or any other online service.
3. What we never do
- No uploads to any server — there is no account system and no backend.
- No selling, renting or sharing of your data with third parties.
- No use of health data for advertising, marketing or data mining.
- No tracking, and no third-party analytics, advertising or data-collection SDKs.
- No false or inaccurate data is written to Apple Health.
4. Content you choose to share
When you share a poster, export CSV files or share a developer recording, the app opens the system share sheet. Where the content goes is entirely your choice, and the receiving app or service handles it under its own privacy policy.
5. Viewing and deleting your data
- Delete a session: on iPhone open the Sessions tab (“记录”), long-press the session and choose “Delete” (workouts already saved in Health are not affected).
- Delete developer recordings: iPhone Settings tab → Recordings, swipe left.
- Delete all local data: delete TennisLooker from your iPhone and Apple Watch.
- Health data: view or delete saved tennis workouts in the Health app; revoke the app’s access any time in iPhone Settings → Health → Data Access & Devices, or on the watch in Settings → Health.
- Motion and Photos access: turn off any time in iPhone Settings → Privacy & Security.
6. Children’s privacy
The app does not collect personal information from anyone, including children.
7. Health notice
TennisLooker is not a medical device. Heart rate, calories and swing speed are estimates from the watch sensors for sports reference only and must not be used for diagnosis or treatment.
8. Changes
If this policy changes, this page will be updated together with the effective date above. Significant changes will also be mentioned in the app’s release notes.
9. Contact
Questions about privacy? Email the developer, Weihao Chen: vikhochan@icloud.com