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Privacy Policy

Last updated: March 20, 2026

Overview

Hanzi Reader is a free Chinese character learning app. Your privacy is important to us. This policy explains what data we collect and how we use it.

Data stored on your device

All learning progress (flashcard states, streaks, settings) is stored locally in your browser's localStorage. This data never leaves your device unless you opt in to cloud sync.

Google Sign-In and Cloud Sync

If you choose to sign in with Google, we access:

• Your Google account name and email (for display purposes only)
• A unique user ID (to store your synced data)

When sync is enabled, your learning progress is stored in Google Firebase Firestore, associated with your Google account. You can sign out at any time to stop syncing. We do not access your contacts, files, or any other Google data.

Data we do NOT collect

• No analytics or tracking
• No cookies (beyond what Firebase Auth requires)
• No advertising
• No data sold to third parties

Third-party services

If you use cloud sync, your data is processed by Google Firebase, subject to Google's Privacy Policy.

Data deletion

To delete your local data, clear your browser's site data for this domain. To delete synced cloud data, sign in, then sign out — or contact us to request deletion.

Contact

Questions about this policy? Open an issue on our GitHub repository.