KanjiBox Privacy Policy

Effective: April 15, 2026

This privacy policy describes how KanjiBox ("we", "the app") handles user data when you use the KanjiBox mobile application.

1. Data We Collect

1.1 Data stored locally on your device

KanjiBox stores the following data exclusively on your device using local storage and an on-device SQLite database:

• Study progress — quiz scores, answer history, and learning statistics.
• App preferences — JLPT level selections, display settings, theme, UI language, and other configuration choices.
• Custom study sets — any personal collections or lists you create.

This data never leaves your device unless you explicitly enable the optional Sync feature (see §1.2).

1.2 Data processed when Sync is enabled

KanjiBox offers an optional account-based synchronisation feature that lets you back up and share your progress across devices. If you choose to use Sync:

• Account credentials — you provide an email address and password to register. Passwords are hashed server-side and never stored in plaintext.
• Sync data — your study progress, preferences, and study sets are transmitted over HTTPS to the KanjiBox sync server and stored there so they can be retrieved from another device.
• Authentication tokens — access and refresh tokens are stored on your device to maintain your session.

1.3 Data we do NOT collect

• We do not collect device identifiers, advertising IDs, or location data.
• We do not use analytics services, crash reporters, or third-party tracking SDKs.
• We do not serve ads or share data with advertisers.
• We do not access your contacts, photos, camera, microphone, SMS, or call log.

2. How We Use Data

All data collected is used solely to provide and improve the KanjiBox app experience:

• Local study data powers your quizzes, progress tracking, and spaced-repetition features.
• Sync data is used only to restore your progress on another device or after a reinstall.

3. How Data Is Shared

We do not sell, rent, or share your personal data with third parties. The only data transmission that occurs is:

• Sync server — if you enable Sync, your encrypted connection sends study data to the KanjiBox sync server operated by the developer. No third parties have access to this server.

4. Data Retention

• Local data remains on your device until you uninstall the app or clear app data.
• Sync data is retained on the sync server for as long as your account is active. You can request deletion of your account and all associated data by contacting support@kanjibox.net.

5. Data Security

We take reasonable measures to protect your data:

• All communication with the sync server uses HTTPS encryption.
• Authentication tokens are stored via the platform's secure key-value storage (Capacitor Preferences, backed by iOS Keychain / Android EncryptedSharedPreferences where available).
• Passwords are never stored in plaintext.

No method of transmission or storage is completely secure. We cannot guarantee absolute security.

6. Permissions

KanjiBox requests only the following device permission:

• Internet access — required for the optional Sync feature and to fetch reference data. The app functions fully offline without it.

7. Children's Privacy

KanjiBox is a general-audience educational app. We do not knowingly collect personal information from children under 13. If you believe a child has provided us with personal data, please contact us and we will delete it promptly.

8. Your Rights

You may at any time:

• Clear all local data by uninstalling the app or clearing app data in your device settings.
• Delete your Sync account and all stored sync data by contacting us.

9. Changes to This Policy

We may update this privacy policy from time to time. Changes will be posted on this page with an updated effective date. Continued use of the app after changes constitutes acceptance of the revised policy.

10. Contact

If you have questions about this privacy policy or your data, contact:

Dave — KanjiBox Developer
Email: support@kanjibox.net