The short version: NTRVL does not collect, store, or transmit any personal data. Everything stays on your device.
NTRVL reads the following from Apple Health with your explicit permission:
NTRVL writes the following to Apple Health:
All data stays on your iPhone and Apple Watch. NTRVL has no server, no backend, no cloud. Your workout history, HR zones, and profile settings are stored locally using Apple's on-device storage (UserDefaults and HealthKit).
Your health data, no. Heart-rate readings, workout records and your profile stay on your device and in Apple Health. They are never uploaded, sold or shared.
The app does send anonymous usage analytics, through a service called TelemetryDeck. This tells us things like: the app was opened, a workout was started, a workout was abandoned during the warm-up, a paywall was viewed. It is how we found out that nobody was finishing a session.
Where a number would be revealing, it is sent as a range rather than a value — an average heart rate arrives as a band, not as a reading, and your age as an age band. There is no account, no name, no email address, no advertising identifier and no ad network. Events are tied to an anonymous identifier for your installation, which cannot be linked back to you.
There are no advertising SDKs and no crash-reporting services in the app.
Workouts run entirely offline — the protocol, the zones and the heart-rate reading need no connection, and none of that leaves your device. The only requests the app makes are the anonymous analytics events described above, and Apple's own servers when you buy or restore a subscription.
ntrvl.app uses Vercel Web Analytics, which counts page views and referrers without cookies and without building a profile of you across sites. The product video is loaded from YouTube only after you press play, so nothing is requested from YouTube if you do not.
NTRVL does not require an account. There is no sign-up, no login, and no email collection.
NTRVL does not knowingly collect data from children under 13. The app is intended for users who can safely perform high-intensity interval training.
If we ever change how data is handled, we will update this page and the "Last updated" date above. Since the app has no server, we cannot push notifications about policy changes — check back here if concerned.
Questions about privacy? Email hello@ntrvl.app.