This Privacy Policy describes how Cairn ("we," "our," or "the App") handles your information. Cairn is designed with one core privacy principle: your data never leaves your device.

1. Camera Access

Cairn requests camera access for one purpose: real-time pose detection during exercise. The camera feed is processed on-device by the MediaPipe Pose Landmarker model to count your exercise repetitions.

• The camera feed is never recorded.
• The camera feed is never stored — not on your device, not anywhere else.
• The camera feed is never transmitted over the internet.
• No photos or videos from the camera are saved at any point.

2. Accessibility Service

Cairn uses the Android Accessibility Service to detect when you visit specific websites, so it can prompt you to do an exercise instead. Here is exactly how it works and what it does and does not do:

• When a browser app is in the foreground, Cairn reads the URL bar text only (e.g., "example.com").
• The URL is compared against a local blocklist of known adult websites that is bundled inside the app.
• If a match is found, Cairn launches the exercise prompt.
• Cairn does not read page content, messages, passwords, or any text beyond the URL bar.
• Cairn does not store the URLs you visit — the comparison happens in memory and is immediately discarded.
• Cairn does not transmit your browsing history to any server. There is no server.
• Cairn does not log which specific websites triggered an interception. Only the count of interceptions is stored locally.

3. Local Data Storage

Cairn stores the following data in your device's local storage (localStorage / SharedPreferences):

• Exercise logs: Number of exercises completed per day (date + count, no details).
• Streak data: Current streak, longest streak (calculated from exercise logs).
• Urge count: Total number of times the exercise prompt was triggered (count only, no URLs or context).
• Settings: Your chosen exercise type, intensity, and commitment reason.
• Onboarding status: Whether you've completed onboarding and the date you started.

This data is stored only on your device. It is never synced to the cloud, never backed up to our servers, and never accessible to us. Uninstalling Cairn permanently deletes all of this data.

4. Internet Access

Cairn requires internet access for one purpose only: loading the MediaPipe pose detection model (a 5.7 MB file) from a Google CDN on first use. This model file is cached by your device's browser after the first load, so subsequent uses work without internet.

No data is sent TO the CDN. Your device downloads the model file; nothing is uploaded.

5. Third-Party Services

Cairn uses the following third-party components, all of which run on your device:

• MediaPipe Tasks Vision (by Google): On-device pose detection model. Processes camera frames locally. No data sent to Google.
• Capacitor (by Ionic): Framework bridge between the web app and Android native features. Does not collect data.
• RevenueCat: Subscription management. Handles Google Play Billing. Receives only the purchase transaction data Google Play generates, which is necessary to verify your subscription.

Cairn does not use any analytics SDKs, advertising SDKs, or tracking SDKs. There are no third-party trackers in this app.

6. What We Don't Do

• We don't collect personal information (name, email, phone number).
• We don't require an account or login.
• We don't track your location.
• We don't read your messages, emails, or notifications.
• We don't share, sell, or rent data — because we don't have any.
• We don't use cookies.
• We don't run analytics or A/B tests on your behavior.

7. Children's Privacy

Cairn is not directed at children under 18. The app is designed for adults seeking to manage their browsing habits through physical exercise. We do not knowingly collect any data from anyone, including children.

8. Data Deletion

To delete all data Cairn has stored: simply uninstall the app. All local data (exercise logs, streaks, settings) will be permanently erased. There is no server-side data to delete because we don't have servers.

9. Changes to This Policy

If we ever change our privacy practices (for example, if we add cloud sync in a future version), we will update this page and notify you in the app before any new feature that processes data differently.

Any future version that adds data collection will require explicit opt-in consent.

10. Contact

If you have questions about this Privacy Policy, contact us at: privacy@cairnhabit.com