Privacy Policy

1. Information We Don't Collect

Duchenne Smile Coach is designed with privacy at its core. The following data never leaves your device:

• Camera feed — Your camera stream is processed in real-time on-device using Apple's Vision framework. It is never recorded, stored, or transmitted.
• Photos and snapshots — Smile snapshots captured during training are stored locally on your device only.
• Facial analysis data — Smile scores, eye crinkle measurements, mouth lift data, and symmetry calculations are computed and stored entirely on your device.
• Personal information — We do not collect your name, email address, or any personally identifiable information through the app.

2. On-Device Processing

All smile analysis is performed using Apple's Vision framework, which runs entirely on your device. This means:

• No internet connection is required for smile analysis
• No images or video frames are sent to any server
• No third-party AI or machine learning services are used
• Processing speed depends only on your device's capabilities

3. Face Data and TrueDepth

This section addresses Apple's Face Data privacy requirements for apps that use the TrueDepth API.

Collection. On supported devices, Duchenne uses Apple's ARKit face tracking during training sessions. The app reads a small fixed set of ARFaceAnchor blendshape coefficients (numeric values between 0 and 1) covering mouth, cheek, eye, brow, and jaw expression channels. The app also reads the face anchor transform to detect head pose so it can ignore frames where you are not facing the camera. The app never reads or saves the TrueDepth depth map, face mesh geometry, any image or video frame from the camera, or any biometric template that could be used to identify you. Devices without a TrueDepth camera fall back to Apple's Vision framework using two-dimensional face landmarks only.

Use. Blendshape values are compared on your device to your neutral-face baseline to produce a 0 to 100 Duchenne smile score and short feedback hints shown in the training UI. Face data is never used for advertising, profiling, model training, research, or identity verification.

Disclosure. Face data is never disclosed to us or to anyone else. The app has no server that receives face data, and we never receive any blendshape values, face anchor transforms, depth data, mesh geometry, image frames, or video frames from your device.

Sharing. No face data is shared with any third-party SDK, advertiser, analytics provider, or other service. The PostHog analytics SDK and the Google AdMob advertising SDK used in the app receive nothing related to face data. The app has no proprietary backend.

Retention. Per-frame face data is held in volatile device memory only and discarded the moment the training session ends. The only data kept after a session is the derived per-session result, namely your smile score, session duration, hint counts, and a snapshot photo if you explicitly tap Capture. These derived results are stored locally on your device in the app's SwiftData store. If you opt into iCloud Backup as a Premium subscriber, the derived results sync to your personal iCloud account via Apple's CloudKit private database, which is accessible only to you under your Apple ID. You can delete this data at any time by deleting the app or by disabling iCloud Backup and managing storage in your iOS Settings.

4. Data Stored on Your Device

The app stores the following data locally on your device:

• Training history — Your smile scores, challenge completions, streak data, and training statistics
• Gallery photos — Smile snapshots captured at peak scores during training sessions
• Achievements — Your unlocked achievements and progress
• Events — Event names and dates you create for event preparation training
• Calibration data — Your neutral face baseline used for accurate scoring
• App preferences — Settings such as sound effects and notification preferences

5. iCloud Backup (Premium)

If you enable iCloud Backup (a Premium feature), your app data is synced to your personal iCloud account using Apple's CloudKit infrastructure. This means:

• Data is encrypted in transit and at rest using Apple's security standards
• Only you can access your backed-up data through your Apple ID
• We cannot access, read, or decrypt your iCloud data
• You can disable iCloud Backup at any time in the app settings

6. Third-Party Services

Apple App Store

If you purchase a Premium subscription, the transaction is handled entirely by Apple through the App Store. We receive a confirmation of your subscription status but do not have access to your payment details. Please refer to Apple's Privacy Policy for details on how Apple handles purchase data.

Advertising (Free Tier)

The free version of Duchenne Smile Coach displays banner advertisements served by Google AdMob. Ads are configured for non-personalised delivery only (the npa=1 flag is set on every ad request) and the app's privacy manifest declares NSPrivacyTracking=false, which means we do not request App Tracking Transparency permission and we do not track you across other apps or websites. We do not share any personal data with advertisers. For details on how AdMob handles ad requests, please refer to Google's Privacy Policy.

7. Analytics

Duchenne Smile Coach uses PostHog to capture anonymous in-app events, such as which screens are viewed and which features are used, so we can improve the app. We do not send any personally identifying information to PostHog. GeoIP and device-detail auto-capture are explicitly disabled in our PostHog configuration. Events are sent to PostHog's EU region (eu.i.posthog.com). For more information see PostHog's Privacy Policy.

8. Notifications

If you grant notification permission, the app sends local notifications to remind you about your daily training streak. These notifications are generated entirely on your device and are not sent through any external push notification service. You can disable notifications at any time in your device's Settings.

9. HealthKit (Optional)

Duchenne Smile Coach can optionally mirror your mood check-ins to Apple Health as State of Mind entries. This integration is fully optional. If you grant HealthKit permission, the app does two things:

• Writes the mood readings you log in Duchenne to your Apple Health store as State of Mind samples.
• Reads back State of Mind samples from your Apple Health store so the in-app trends view can include mood readings you logged through Apple Health or other wellness apps.

Health data stays on your device and in your personal Apple Health store. We never receive your health data, we never store it on any server, and we never share it with any third party. You can revoke HealthKit permission at any time in iOS Settings, Privacy & Security, Health, Duchenne. Denying HealthKit permission does not block any feature in Duchenne. Mood check-ins still save locally inside the app.

10. Children's Privacy

Duchenne Smile Coach is not directed at children under the age of 13. We do not knowingly collect any information from children. The app does not require account creation or any personal information to use.

11. Data Deletion

Since all data is stored on your device, you have full control over it:

• Delete individual photos from the Gallery within the app
• Reset calibration data from the Profile screen
• Delete all app data by deleting the app from your device
• Delete iCloud data by disabling iCloud Backup in the app, then managing storage in your device's iCloud settings

12. Changes to This Policy

We may update this Privacy Policy from time to time. Any changes will be reflected on this page with an updated "Last updated" date. We encourage you to review this policy periodically.

13. Contact Us

If you have any questions about this Privacy Policy or the app's privacy practices, please contact us at:

[email protected]