The short version: Your health data stays on your phone. Zone2 Index has no accounts and no servers that hold your data. The one time anything leaves your device is a small, anonymous summary used to write your coach insights, and only when an insight is generated.
Zone2 Index is an iOS app that reads your existing Apple Health data and computes a Zone 2 fitness score entirely on your device. There is no account to create and no profile on any server. This policy explains exactly what data is involved and where it goes.
Zone2 Index reads activity, heart rate, heart-rate variability, resting heart rate, VO2 max, and sleep data from Apple HealthKit with your permission. This raw health data is read on your device, stored only on your device, and never sent to us or anyone else. We do not operate a database of your health data, because we never receive it.
Under privacy laws including GDPR, CCPA, and Washington's My Health My Data Act, we are not a data controller for your health data: that data never leaves your possession. Apple HealthKit is the source, and your own device (and your own iCloud, below) is the storage.
When the app generates a written insight, it sends a small, anonymized JSON summary to a Cloudflare Worker that relays it to Anthropic's Claude API and returns the written text. This summary contains derived metrics and changes (for example, a score delta or a threshold), not raw samples and not anything that identifies you. There is no name, no email, no account id, and no raw heart-rate stream in it.
The relay holds no database and does not log the contents of these requests; it counts requests for rate limiting only. Anthropic processes the request to produce the text and does not use it to train its models; both the relay and the API retain only their standard short-lived operational logs. Insights are generated only at specific moments (such as a weekly digest or a meaningful score move), not continuously.
Your app-created data (your goal, check-ins, achievements, planned sessions, your signed vision, weekly-streak state) is backed up to your own iCloud using Apple's end-to-end-encrypted key-value store. Apple encrypts it; we have no key and never see it. Your raw health data is not backed up, it is simply re-read from Apple Health when you reinstall. This backup exists so a reinstall does not lose your history.
Subscriptions and the lifetime purchase are processed entirely by Apple through the App Store. We never see your name, payment details, or card information. Your purchase is verified on your device by reading the App Store receipt; there is no purchase server on our side.
Version 1 of Zone2 Index ships with no analytics SDKs and no advertising. We do not track you across apps or websites. We do not sell or share your data, because we do not collect it.
Zone2 Index is not directed to children under 13 and does not knowingly collect data from them. The app is intended for adults managing their own training.
If this policy changes, the updated date above will change and the new version will be posted at this address. Material changes will be reflected in the app as well.
Questions about privacy: quices@hotmail.com.