Last updated: May 2026
Watter is a free indoor cycling training app. This policy explains what data the app collects, why, and how it is handled.
| Data | Where it goes | Why |
|---|---|---|
| Anonymous usage events (screen views, feature usage, Bluetooth device names, FTP value) | PostHog — EU servers (eu.i.posthog.com) |
Understand how the app is used and prioritise improvements |
| Crash reports and error logs | Sentry | Identify and fix bugs |
| Strava athlete name and ID | Your device only (SQLite) | Displayed in the Connections screen after you connect Strava |
| Strava OAuth tokens (access + refresh) | Your device only (iOS Keychain) | Authenticate Strava uploads on your behalf |
| Workout metrics (power, heart rate, cadence) | Your device only (SQLite) | Ride history and TCX export |
| Voice audio (if AI workout feature is used) | Watter backend — transcribed and discarded immediately | Convert your spoken description into a structured workout |
| Workout generation prompts and FTP value | Watter backend → OpenAI | Generate ERG workout via AI |
Usage events are sent to PostHog's EU-hosted infrastructure. Events include anonymous identifiers only — no name, email, or device serial number is attached. PostHog's privacy policy is available at posthog.com/privacy. You can opt out by disabling analytics in your device's app settings (if available) or by contacting us.
If the app crashes, an error report is sent to Sentry. Reports contain device model, OS version, app version, and a stack trace. No screenshots, no personal identifiers. Sentry's privacy policy is at sentry.io/privacy.
Connecting Strava is optional. If you connect, your Strava OAuth tokens are stored in the iOS Keychain on your device. Completed workouts are uploaded to Strava only if you enable auto-upload, or if you manually export them. You can disconnect Strava at any time in the Connections screen, which removes all stored tokens.
We do not sell, rent, or share your data with third parties for advertising or marketing purposes. Data is shared only with the processors listed above (PostHog, Sentry, OpenAI) strictly to provide the app's features.
Workout data stored on your device is kept until you delete the app or manually delete individual workouts. Analytics and crash data are retained according to PostHog's and Sentry's own retention policies (typically 12–24 months).
Watter is not directed at children under 13. We do not knowingly collect data from children.
If we make material changes, we will update the date at the top of this page. Continued use of the app after changes constitutes acceptance.
Questions or requests (data deletion, opt-out): [email protected]