Privacy Policy
On-device, read-only Apple Health, no account needed
Last updated October 2, 2026
01What we read from Apple Health
With your permission, the app requests read-only access to:
- Wrist temperature (sleeping)
- Respiratory rate
- Heart rate variability (HRV / SDNN)
- Resting heart rate
- Sleep analysis (asleep time)
- Workouts (for context)
The app does not write samples to Apple Health. You can revoke access anytime in the Health app under Sharing → Apps → Early Signal.
02Where data is stored
Daily metrics, personal baselines, assessments, and optional check-ins are stored locally on your device using iOS data protection. Processing happens on-device. There is no cloud account or sync.
03Data silos and model training
On-device computing. We maintain strict data silos. Your personal health metrics, biometric logs, and tracking data stay on your iPhone. They are not sold, not used for advertising, and not used to train external AI or language models. The marketing site does not receive those logs.
04Notifications
If you allow notifications, Off from usual alerts, optional Pro Slightly off alerts, and follow-up prompts are scheduled locally on your device. Exact health values are not shown on the lock screen by default; you can opt in to detailed previews in Settings. You can also pause alerts for a set number of days.
05Analytics (optional)
Product analytics are opt-in and local. Events do not include raw health values. If you opt in, you can export an event log from Settings. We do not sell data, use it for advertising, or train a general-purpose model on health data.
06This website
The marketing site does not collect health data. It uses Google Analytics to measure visits. Google may set cookies (such as _ga) and receive usage data, including pages viewed. You can block those cookies in your browser. Standard web server logs (for example IP address and user agent) may be processed by our hosting provider to operate and secure the site.
07Waitlist emails
If you join the waitlist, we collect your email address, the time of signup, and optionally your browser user agent. We use that only to tell you when Early Signal is on the App Store and for occasional product notes. You can unsubscribe from any email, or ask us to delete your address at .
We use Cloudflare Turnstile on the waitlist form to reduce spam. That check may involve your IP address and limited device signals. Waitlist addresses are stored with SendFox, which we use to send the launch email.
08Your controls
- Delete all app data from Settings (removes local records and scheduled notifications)
- Disconnect Apple Health access in the Health app
- Turn off or pause notifications in the app or iOS Settings
- Opt out of local analytics anytime
- Leave the waitlist or delete your email by unsubscribing or writing to
09Children
Early Signal is intended for adults. It is not directed at children under 13.