Zzz Polyrhythm — Privacy Policy

App Name:

Zzz Polyrhythm (Android)

Last Updated:

May 26, 2026

Effective Date:

2026-05-26

1. Our Privacy Stance

This app ("Zzz Polyrhythm", "the App") respects your privacy to the fullest extent. All rhythm-related configurations (time signature, BPM, layered rhythms, voices, saved presets) and your language preference are processed and stored entirely on your device, and are never transmitted to any server operated by us.

However, to keep the App available for free, we display banner and full-screen (interstitial) ads through a third-party advertising network (Google AdMob). Ad delivery involves transmitting your IP address and Android Advertising ID (AAID) to the ad network.

2. Information We Collect

2.1 Rhythm Configurations & Presets

• Time signature, BPM, voices, layered rhythms, and shuffle settings you adjust on screen are held in memory.
• When you save a named preset (a Premium-only feature), it is written to the App's private storage area as a JSON file.
• None of this data is transmitted to our servers or any cloud service.

2.2 Language & Locale Settings

• The display language you select from the hamburger menu (System, English, Japanese, Chinese, Korean, Spanish, Portuguese) is saved to the device's SharedPreferences.
• The OS locale is used only for date/number string formatting; it is not stored or transmitted.

2.3 Subscription Purchase Information

• When you toggle "Ad-free (Premium)" on, a subscription is purchased through Google Play Billing.
• The purchase token and status (active / canceled) are obtained from Google Play and stored as a flag in the device's SharedPreferences.
• Payment information such as credit card numbers is handled entirely by Google Play; the App never receives or stores it.

3. How We Use Information

Collected information is used solely for the following purposes:

• Controlling on-device metronome playback
• Saving and loading local presets at your request
• Displaying the UI in your selected language
• Toggling ad display and unlocking restricted features based on subscription status

4. Where Information Is Stored

Rhythm configurations, presets, language preference, and the subscription status flag are all stored only on your device.

• Saved to the App's private internal storage area

• No transmission to our servers
• No cloud sync
• No mechanism by which the developer can access your data

Data associated with ad delivery is obtained and managed independently by third-party ad providers, separately from data stored by the App.

5. Sharing with Third Parties

We do not sell or provide the following to third parties:

• Rhythm configurations or preset contents
• Language selection history
• Detailed app usage activity
• Personally identifying information

However, for ad delivery (Google AdMob), Google and partner ad providers receive your IP address, Android Advertising ID (AAID), device/OS information, and ad impression/interaction metrics. The App's developer cannot access this data, nor do we link it with on-device rhythm settings or share such linkage with third parties.

6. Third-Party Services

6.1 Google AdMob (Ad Delivery)

To keep the App free, we deliver banner and interstitial ads through Google AdMob.

Data Sent	IP address, Android Advertising ID (AAID), device/OS information, ad impression/interaction metrics
Data NOT Sent	Rhythm settings, saved presets, language preference, any other on-device data
Purpose	Ad delivery, display, frequency capping, performance measurement, fraud prevention
Data Controller	Google LLC and partner ad providers (processed per their respective privacy policies)

Google AdMob Privacy Policy: https://policies.google.com/privacy

You can reset your Advertising ID or opt out of personalized ads from your Android device's Settings → Google → Ads.

6.2 Google Play Billing (Subscriptions)

The "Ad-free (Premium)" monthly subscription is provided through the Google Play Billing Library. All payment processing, billing management, and cancellation are handled by Google Play.

• The App only receives the purchase token and purchase status from Google Play.
• The App never obtains or stores payment information such as credit card numbers or bank account details.
• You can cancel your subscription anytime via the Google Play Store's "Subscriptions" settings.

6.3 Consent Management for EU, UK, and Regulated U.S. States

To comply with the GDPR (EU/EEA and UK) and U.S. state privacy laws (CCPA/CPRA, etc.), users in eligible regions are presented with a consent form on first launch via Google's User Messaging Platform (UMP). Your consent choices control whether personalized ads are delivered.

7. Required Permissions (Android)

Permission	Purpose
android.permission.INTERNET	Loading ads and communicating with Google Play Billing
android.permission.ACCESS_NETWORK_STATE	Checking network connectivity (used by ad SDK)
com.android.vending.BILLING	Subscription processing via Google Play

No additional permissions for location, microphone, camera, contacts, storage, notifications, or background execution are required.

8. What We Do NOT Use

• Analytics SDKs (Firebase Analytics, Google Analytics, etc.)
• Crash reporting SDKs (Firebase Crashlytics, etc.)
• User authentication or login
• Social media integration
• Backend servers operated by the developer
• Cloud processing (all audio processing is done by the on-device C++ engine)
• Location, microphone, camera, contacts, background execution

* We use Google AdMob solely for ad delivery and Google Play Billing solely for subscriptions.

9. Data Deletion

When you uninstall this App, all data created by the App on your device (saved presets, language preference, subscription status flag, etc.) is completely deleted.

To delete individual presets, use the in-app "Load" dialog (Premium feature) — check the items you want to remove and tap delete.

10. Children's Privacy

This App does not knowingly collect personal information from children under 13. Any ads shown in the App are delivered in accordance with Google AdMob's policies and your selected consent preferences.

11. Open-Source Libraries

This App uses the following open-source software:

• Google Oboe 1.9 (Apache License 2.0) — low-latency audio engine
• Jetpack Compose / Material 3 (Apache License 2.0) — UI framework
• Dagger Hilt 2.52 (Apache License 2.0) — dependency injection
• Kotlin Coroutines (Apache License 2.0) — asynchronous programming
• kotlinx.serialization (Apache License 2.0) — JSON serialization
• AndroidX Lifecycle / Activity / AppCompat / SplashScreen (Apache License 2.0)
• Google Play Services Ads (Google APIs Terms of Service)
• Google Play Billing Library (Google APIs Terms of Service)

Integration and configuration of these libraries are the original implementation of the App developer.

12. Changes to This Policy

This policy may be updated without prior notice. Significant changes will be communicated along with App updates. This page is always the most current version.

13. Contact

For inquiries regarding this policy, please contact us through this App's Google Play Store listing.