Effective date: September 17, 2026
Just Zones is a heart-rate zone analysis app for iPhone. This page explains what data it reads, what stays on your device, and what the third-party services it uses receive.
Just Zones reads workout and heart-rate data from Apple Health (HealthKit) — workouts, heart-rate samples, resting heart rate, workout routes (location), and swimming distance and stroke counts — to compute your time-in-zone charts. This data is read on-device only and processed on-device only. Just Zones never uploads your Health data anywhere, and it does not write anything back to Health. Zone settings you enter yourself (max heart rate, resting heart rate, LTHR, age, zone boundaries) are stored locally on your device as app settings, not in Health.
Just Zones has no user accounts, no sign-in, and no backend server of its own.
Just Zones uses Firebase Crashlytics, a service from Google, to receive crash reports so problems can be fixed. When the app crashes, Crashlytics receives a crash log along with your device model, OS version, and an anonymous installation identifier. This does not include any of your Health data. See Google's Firebase privacy policy: firebase.google.com/support/privacy.
The one-time Pro unlock is processed through RevenueCat, which receives purchase and App Store receipt information along with an anonymous app user identifier, used to check and restore your Pro entitlement. This does not include any of your Health data. See RevenueCat's privacy policy: revenuecat.com/privacy.
Because Health data is processed on-device and never leaves it, deleting the app deletes your local Just Zones data, including zone settings and its local cache. To request deletion of anonymous crash or purchase records held by Crashlytics or RevenueCat, or with any other privacy question, contact us below.