Privacy Policy

App: Shadow Flow | Last Updated: June 7, 2026

Summary: Shadow Flow is a language-shadowing application. Your practice data and voice recordings remain on your device. We do not sell, rent, or share your personal data for advertising purposes. Microphone access is used only for recording practice sessions within the app.

1. Who We Are

Shadow Flow ("we", "our", or "us") is developed and operated by Keith Cheng. This Privacy Policy explains how information is handled when you use the app.

2. Information We Collect

2.1 Information You Provide

2.2 Information Generated Automatically

3. How We Use Information

Information

Purpose

Storage

Google OAuth Token

Access YouTube playlists and subscriptions

Exchange processed by developer backend; token stored encrypted on device only

Voice Recordings

Shadowing practice playback

Device only

Practice Data

Resume learning progress

Device only

Saved Subtitles

Personal learning library

Device only

Crash Reports

Bug fixing and app stability

Firebase

Anonymous Analytics

Improve app features

Firebase

4. Microphone Permission

Shadow Flow requests microphone access only when you use voice recording features.

You may revoke microphone permission at any time through your device settings.

5. Google Sign-In and YouTube Services

Shadow Flow uses Google Sign-In and YouTube Data API services. When you use these features, Google's own privacy practices also apply.

We request only read-only YouTube access necessary to retrieve playlists and subscriptions. We do not create, modify, upload, or delete content on your YouTube account.

To complete the sign-in process, the OAuth authorization code is sent to a developer-controlled backend server, which exchanges it for access and refresh tokens using Google's token endpoint. The backend server does not persistently store your OAuth tokens or any YouTube account data; tokens are immediately returned to the app and stored encrypted on your device only. Shadow Flow's use and transfer of information received from Google APIs complies with the Google API Services User Data Policy, including the Limited Use requirements.

6. Firebase Analytics and Crashlytics

Firebase services provided by Google LLC may collect:

No voice recordings or saved learning content are transmitted through Firebase.

7. Third-Party Services

The app relies on the following third-party services:

These providers process data according to their own privacy policies.

8. Data Sharing

We do not sell, rent, or trade personal information.

Information may only be disclosed:

9. Data Retention and Deletion

Practice data, saved subtitles, and voice recordings remain on your device and are generally removed when the app is uninstalled.

Google account access tokens are removed when you sign out or revoke app access through your Google Account settings.

To request deletion of Firebase-related data associated with your device, please contact us using the information provided below and include your Firebase Installation ID if available.

10. Children's Privacy

Shadow Flow is not intended for children under the minimum age required by applicable laws in their country or region. We do not knowingly collect personal information from children.

11. Security

Sensitive data such as authentication tokens may be stored using Android security mechanisms including encrypted storage and Android Keystore protections. While we take reasonable measures to protect information, no method of storage or transmission is completely secure.

12. Your Rights

Depending on your location, you may have rights regarding access, correction, or deletion of personal information. Most app data is stored locally and can be managed directly on your device.

13. Changes to This Privacy Policy

We may update this Privacy Policy from time to time. Any updates will be reflected by revising the "Last Updated" date at the top of this page.

14. Contact Us

If you have questions, concerns, or requests regarding this Privacy Policy: