SmartSleep Privacy Policy

Last Updated: January 4, 2026

1. Introduction

SmartSleep ("the App") is an Apple Watch-exclusive sleep tracking and smart alarm application. This Privacy Policy explains what information the App collects and how it is used.

            Key Point: SmartSleep stores all collected data locally on your device. No data is
            transmitted to the cloud or any server.
        

2. Information We Collect

The App collects the following health data through Apple's HealthKit:

Heart Rate Data - Monitors your heart rate during sleep to estimate sleep stages
Heart Rate Variability (HRV) Data - Used to assess sleep quality and distinguish between deep and light sleep
Motion Sensor Data - Detects body movement to determine sleep onset, wake times, and sleep stages
Sleep Data - Records sleep sessions (start time, end time, total sleep duration, etc.)

3. How We Use Your Data

Collected data is used solely for the following purposes:

Automatic sleep detection (detecting heart rate decrease and reduced movement)
Sleep stage estimation (identifying deep sleep, light sleep, and awake periods)
Smart alarm functionality (detecting light sleep 15 minutes before scheduled wake time for optimal awakening)
Sleep score calculation (0-100 rating based on sleep duration, deep sleep percentage, awakenings, and HRV)
Sleep history display (weekly/monthly charts, average scores, etc.)
Saving sleep data to HealthKit (enabling integration with other health apps)

4. Data Storage

All data is stored locally on your device.

Collected data is saved within your iPhone and Apple Watch using SwiftData
No data is transmitted to external servers, cloud services, or third parties
The developer has no access to your health data or personal information

5. Data Sharing

The App does not share your data with any third parties.

No data sharing for analytics or advertising purposes
Data can only be shared with other health apps through Apple HealthKit when you explicitly choose to do so
iPhone ⇔ Apple Watch data synchronization is performed locally using the WatchConnectivity framework

6. HealthKit Usage

The App uses Apple's HealthKit framework:

Read Permission: Reading heart rate, heart rate variability, and sleep analysis data
Write Permission: Saving sleep session data to HealthKit
HealthKit access requires your permission upon first launch
You can change or revoke permissions anytime through iOS Settings

7. Data Retention

The App retains sleep data until you delete it:

Sleep session data is saved until you manually delete it
Uninstalling the app will delete all local data
Data saved to HealthKit can be managed through the iOS "Health" app

8. Security

We take the following measures to ensure your data security:

All data is stored in iOS's encrypted storage
No network communication (zero risk of data leakage)
Apple Watch synchronization uses the secure WatchConnectivity framework

9. Your Rights

You have the following rights:

Access: View your sleep data anytime within the app
Deletion: Delete sleep session data individually
Data Portability: Export data to other apps through HealthKit
Opt-out: Revoke HealthKit access permissions anytime through iOS Settings

10. Third-Party Services

The App uses no third-party services except:

Apple HealthKit: Apple's official healthcare framework (compliant with Apple's Privacy Policy)

No third-party SDKs such as analytics tools, ad networks, or crash reporting services are used.

11. Children's Privacy

The App is not intended for children under 13. We do not knowingly collect personal information from children under 13.

12. Changes to This Privacy Policy

This Privacy Policy may be updated as necessary. Significant changes will be communicated through in-app notifications or update notes.

13. Governing Law

This Privacy Policy shall be governed by and construed in accordance with the laws of Japan.