Privacy Policy

Last Modified: March 13, 2026

Longtang is designed to work entirely offline. We do not collect, store, or transmit any personal data. Your learning progress stays on your device.

Data Collection

We do not collect any data. Specifically:

  • No personal information (name, email, phone number)
  • No usage analytics or tracking
  • No crash reporting or diagnostics sent to our servers
  • No cookies or advertising identifiers
  • No location data
  • No access to contacts, camera, microphone, or photos
  • No background clipboard monitoring — clipboard is only read when you switch to the app, and only if you opt in

Data Storage

All app data is stored locally on your device:

  • Dictionary database: Bundled with the app, read-only
  • Vocabulary lists: Stored in a local SQLite database on your device
  • Review progress: Stored locally using the FSRS spaced repetition algorithm
  • Settings and preferences: Stored locally on your device

This data is not accessible to us or any third party. If you delete the app, all local data is permanently removed.

Third-Party Services

Longtang does not integrate with any third-party analytics, advertising, or tracking services.

The app uses your device’s built-in text-to-speech engine for pronunciation. This is processed entirely on your device — no audio data is sent to external servers.

If you enable the optional clipboard detection feature, Longtang checks your clipboard for Chinese text only when the app comes to the foreground — never in the background. Clipboard content is processed on-device and is never transmitted anywhere. You can disable this feature at any time in Settings.

In-App Purchases

If you purchased Longtang through the Apple App Store or Google Play Store, your payment is processed by Apple or Google respectively. We do not have access to your payment information. Please refer to Apple’s Privacy Policy or Google’s Privacy Policy for details on how they handle payment data.

Children’s Privacy

Longtang does not knowingly collect any information from children under 13. Since we collect no data from any user, this applies universally.

Changes to This Policy

If we update this privacy policy, we will post the revised version at this URL with an updated effective date. Since we collect no data, meaningful changes are unlikely.

Contact

If you have questions about this privacy policy:

This privacy policy applies to all versions of Longtang, including the English, German, and French editions, across all platforms (iOS and Android).