Fillorin

Privacy Policy

Last Updated: October 25, 2026

Fillorin ("we", "our", or "us") operates the Learn Japanese app for iOS and Android. This Privacy Policy explains what data we collect, why we collect it, how it is stored and synced, and how you can delete it.

By creating an account or using Learn Japanese, you agree to the practices described in this policy.

1. What Data We Collect

We collect only what is needed to run the app and keep your progress safe across devices.

• Account information: When you sign in (with Google, Apple, or email), we receive your email address and an ID that identifies your account. We never see or store your password — sign-in is handled by Google Firebase Authentication, and by Apple when you use Sign in with Apple (which lets you hide your real email address).
• Study progress: Your learning activity, including vocabulary, kanji drawing, and reading. This is kept on your device and securely backed up to your private account on our backend (operated for us by Cloudflare) when you are online.
• Public profile: If you use friends, leaderboards, races, or contests, you choose a public name and avatar. Your public name, avatar, level, experience points, and contest results are visible to other users. Friend connections are stored so you can see each other's progress.
• Purchases: If you subscribe to Learn Japanese Pro, the App Store or Google Play processes the payment. We receive confirmation of your subscription (plan, status, and renewal date) linked to your account ID — never your card or bank details.
• Notifications: If you allow notifications, your device gets a push token so we can send study reminders and friend or contest updates. You can turn them off at any time in the app or your device settings.

We do not collect your phone number, precise location, contacts, or any card or bank details. We do not need your real name — your public name can be anything you choose.

2. How Your Progress Is Synced

Your study data lives primarily on your device. When the app is online, it backs up your progress to your private cloud account so it's available if you switch devices or reinstall.

• When sync happens: Your progress is synced when you minimise or close the app. Only what has changed since the last sync is uploaded, which keeps data usage low.
• Offline use: If there is no internet connection, the app continues working fully from your device. Your data will sync the next time a connection is available.
• Data isolation: Your synced data is tied to your own account, and no other user can access your records.

3. App Integrity, Versioning & Maintenance

To keep the app secure and working correctly, Learn Japanese communicates with our secure backend (operated for us by Cloudflare). This service:

• Verifies the app is a genuine, untampered build.
• Checks that you are running a supported version, and flags outdated versions.
• Signals planned maintenance windows.
• Loads the app's study content and configuration.

These checks transmit only your app's version code and a security token — no personal information and no learning data is sent.

4. Third-Party Services

Learn Japanese uses the following external services to function:

• Google Firebase Authentication & Cloud Messaging — handles secure sign-in, and delivers push notifications if you allow them. Firebase Privacy Policy ↗
• Firebase Analytics — collects anonymous, aggregated usage data (e.g. which study modes are used) and retention, not tied to your identity, to help us improve features. Firebase Privacy Policy ↗
• Firebase Crashlytics — collects crash and error reports, with device and OS details (not your identity), so we can diagnose and fix problems. Firebase Privacy Policy ↗
• Firebase Performance Monitoring — measures app start-up time and responsiveness so we can keep the app fast. Firebase Privacy Policy ↗
• Cloudflare — operates our backend, which stores your synced progress and community data (public profile, friends, leaderboards, contests) and runs app-integrity checks, version & maintenance gating, and study-content delivery (see Section 3). Cloudflare Privacy Policy ↗
• Google ML Kit — powers on-device handwriting recognition and translation. Your drawings are processed entirely on your device and are never sent to our servers. ML Kit Terms ↗
• Tatoeba — example sentences are loaded on demand from tatoeba.org; your device's IP address is shared with Tatoeba only when fetching a sentence.
• Apple App Store & Google Play Billing — process subscription payments. Apple Privacy Policy ↗ · Google Privacy Policy ↗
• RevenueCat — verifies your subscription with the App Store or Google Play and keeps Pro active across your devices. It receives your account ID and purchase receipts, not your name or payment details. RevenueCat Privacy Policy ↗
• Google AdMob — serves ads in the free version of the app (see Section 5). Google Privacy Policy ↗

You can turn off all analytics, crash reporting, and performance diagnostics at any time in Settings → About & Legal → "Share anonymous diagnostics." In the EEA, UK, and Switzerland this collection is additionally gated by your consent choice.

Aside from the anonymous, aggregated analytics described above, we do not use data brokers, and we never sell your personal data or share it with third parties beyond the services listed here.

5. Advertising

The free version of Learn Japanese is supported by advertising, served by Google AdMob. Ads appear only between study activities — never during writing practice, reviews, or quizzes.

• What AdMob collects: to serve and measure ads, Google may collect your device's advertising ID, IP address, and general device information, as described in the Google Privacy Policy and How Google uses data from partner apps.
• Your consent (EEA, UK & Switzerland): before any personalized ads are shown, you will see a consent message and can choose non-personalized ads instead. You can change your choice at any time from the app's settings.
• iPhone and iPad: the app asks your permission (App Tracking Transparency) before your device's advertising identifier is used. If you decline, you will only see non-personalized ads. You can change this at any time in Settings → Privacy & Security → Tracking.
• Your controls: on Android you can reset or delete your advertising ID at any time in Settings → Privacy → Ads.
• Pro subscribers see no ads.

We never share your learning data or account information with advertisers.

6. Deleting Your Account and Data

• Delete your account in-app (preferred): Open the app and go to Profile → Danger zone → Delete Account. This immediately removes all your synced progress from the cloud and permanently deletes your account. There is no waiting period and no data is retained after deletion. Deleting your account does not cancel a Pro subscription — cancel it in your App Store or Google Play account settings.
• Request deletion or export from the web: If you cannot access the app, use the self-service forms on our Data Deletion page or Data Export page. Enter your registered email and we'll send a verification link to confirm the request is yours. Deletion permanently removes your account and data; export sends you a full copy of it. Both are processed within 7 working days, with a final confirmation email when complete.
• Local data: Uninstalling the app removes the app's data from your device. If you have already deleted your account before uninstalling, all copies of your data — both local and cloud — will be gone.

7. Data Retention

We retain your data for as long as your account exists. If you delete your account, all associated data is deleted immediately from our systems. We do not keep backups of deleted user data.

8. Children's Privacy

Learn Japanese is a language-learning app suitable for a general audience. We do not knowingly collect any personal data beyond what is described in this policy. The app's built-in dictionary (JMdict) is a comprehensive Japanese–English reference and may contain vocabulary covering a broad range of topics. Parents or guardians should use their own discretion regarding app usage for younger children. If you have concerns about a child's account or data, please contact us and we will address it promptly.

9. Open-Source Licenses

Learn Japanese is built on outstanding open-source projects. Their licenses are reproduced in full below as required by their terms.

10. Policy Updates

We may update this Privacy Policy from time to time. When we do, we will revise the "Last Updated" date at the top of this page. We encourage you to review this page periodically. Continued use of the app after changes constitutes acceptance of the updated policy.

11. Contact Us

If you have any questions about this Privacy Policy or your personal data, please contact us:

support@fillorin.com