Last updated 9 November 2026
Halo is a personal health tracker for iPhone. It reads your health data, with read-only access, from the source you connect: Fitbit through the Google Health API, Apple Health (iPhone and Apple Watch), or Whoop. It works out its scores on your iPhone.
Sleep, heart rate, heart rate variability, resting heart rate, recovery, workouts, steps and activity, calories, breathing rate, blood oxygen, skin temperature and weight, only as allowed by the permissions you grant. Halo never writes to any of these services.
Your health data stays on your iPhone. Halo has no servers that store it, no accounts, no analytics and no advertising. It never sells, shares or transfers your data to anyone, and never uses it for advertising or to train any model.
When you connect Fitbit, Halo uses Google sign-in to read your activity and fitness, health metrics and sleep from the Google Health API, read-only. That data is used only to show your own scores, graphs and widgets on your iPhone, and is stored only on your iPhone. Halo's use and transfer of information received from Google APIs adheres to the Google API Services User Data Policy, including the Limited Use requirements.
Sign-in tokens are kept in your iPhone's Keychain. For Whoop, sign-in passes through a small service that swaps a sign-in code for an access token and stores nothing.
Subscriptions are bought and managed by Apple through the App Store. Halo only learns whether your subscription is active; it never sees your payment details.
Disconnect a source in Halo's Settings, use Settings › Delete all data, revoke access in your Google account, Apple Health or Whoop, or delete the app to remove everything it stored.
Halo is not directed at children under 13.
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