Privacy Policy

Last updated: May 24, 2026

1. Introduction

D3-Sync ("we", "our", or "us") respects your privacy and is committed to protecting your personal data. This privacy policy informs you about how we collect, use, and look after your personal data when you use our iOS and watchOS application, in compliance with Apple App Store Connect guidelines.

2. Data Collection and Usage

We collect and use the following types of data solely to provide the core functionality of the app:

• Health Data (Apple HealthKit): D3-Sync integrates with Apple Health (HealthKit) to read and write your dietary Vitamin D levels, as well as read your Fitzpatrick skin type. All health data is stored securely on your device and in your personal iCloud. We do not transmit, collect, or store your health data on our own servers. The data is used exclusively to display your daily progress and keep your Health profile updated. We do not use this data for marketing, advertising, or data mining.
• Location Data: To accurately calculate UV exposure, the app requests access to your location. Location data is sent anonymously to Apple WeatherKit to fetch the local UV index. We do not track or store your location history on external servers. Passive tracking relies entirely on local iOS geofencing.
• Push Notification Tokens: If you enable passive tracking, an anonymous device token is generated to send silent background push notifications to wake the app for local calculations. No personal or health data is attached to this token.

3. Data Retention and Deletion

Because your health and location data are stored locally on your device, we do not retain any of this data on our servers. You have full control over your data:

• You can delete your health data directly through the Apple Health app at any time.
• You can revoke location and HealthKit permissions in your iOS Settings at any time.

4. Third-Party Services

We do not sell, trade, or otherwise transfer your Personally Identifiable Information to outside parties. The app only communicates with Apple-provided services (WeatherKit, HealthKit, CloudKit) to function.

5. Contact Us

If you have any questions about this privacy policy or your data rights, please contact our support team.