Fillorin

Privacy Policy

Last Updated: June 08, 2026

Fillorin ("we", "our", or "us") operates the Study Japanese Android application. 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 Study 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 (via Google or email), we receive your email address and a unique user ID generated by Firebase Authentication. No passwords are stored by us — authentication is handled entirely by Google.
Study progress: Your study progress, including vocabulary, kanji drawing, reading, and other learning activity. This is stored locally on your device in a SQLite database (via Android Room) and synced to Google Cloud Firestore when you are online.

We do not collect your name, phone number, location, or any payment information.

2. How Your Progress Is Synced

Your study data lives primarily on your device. When the app is online, it syncs changes to Google Cloud Firestore so your progress is available if you switch devices or reinstall.

When sync happens: Your progress is synced when you minimise or close the app. Only records that have changed since the last sync are uploaded, identified by a lastTs timestamp. This keeps data usage low.
Offline use: If there is no internet connection, the app continues working fully from the local database. Your data will sync the next time a connection is available.
Data isolation: Your synced data is stored under your unique Firebase User ID. No other user can access your records.

3. App Version Checks

The app periodically checks our server to verify it is running a supported version. This lets us flag outdated versions or announce maintenance windows. No personal data is sent during this check — only your app's version code.

4. Third-Party Services

Study Japanese uses the following external services to function:

Google Firebase Authentication — handles secure sign-in. Firebase Privacy Policy ↗
Google Cloud Firestore — stores your synced progress data. Google Cloud Privacy Notice ↗
Firebase Remote Config — used for app version checks only.

We do not use advertising SDKs, analytics platforms, or any data brokers. No data is sold or shared with third parties beyond the Google services listed above.

5. Deleting Your Account and Data

You are in full control. The fastest way to delete your data is directly inside the app via Settings → Delete Account — it is instant and requires no waiting. If you can no longer access the app, you can request deletion by email. See the full details on our Data Deletion page.

Delete your account in-app (preferred): Open the app, go to Settings → Delete Account from the home screen. This immediately removes all your study progress from Cloud Firestore and permanently deletes your Firebase Authentication account. There is no waiting period and no data is retained after deletion.
Request deletion by email: If you cannot access the app, email support@fillorin.com from the exact address you used to register. Support will reply with a confirmation request — you must reply to that email to authorise the deletion. Your account and all data will be permanently deleted within 7 working days, depending on the queue. You will receive a final confirmation email when deletion is complete.
Local data: Uninstalling the app removes the local database from your device. If you have already deleted your account before uninstalling, all copies of your data — both local and cloud — will be gone.

6. 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.

7. Children's Privacy

Study 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.

8. Open-Source Licenses

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

JMdict & KANJIDIC — Electronic Dictionary Research and Development Group CC BY-SA 4.0

This app uses the JMdict and KANJIDIC dictionary files, which are the property of the Electronic Dictionary Research and Development Group (EDRDG) and are used in conformance with the Group's licence.

License: Creative Commons Attribution-ShareAlike 4.0 International (CC BY-SA 4.0)
Copyright © 2026 Electronic Dictionary Research and Development Group

Full license terms: http://www.edrdg.org/edrdg/licence.html ↗
CC BY-SA 4.0 summary: https://creativecommons.org/licenses/by-sa/4.0/ ↗

KanjiVG — Ulrich Apel CC BY-SA 3.0

Kanji stroke-order SVG data is sourced from KanjiVG, created by Ulrich Apel.

Full license terms: https://creativecommons.org/licenses/by-sa/3.0/ ↗

LXGW WenKai Lite — CJK Typeface OFL 1.1

The typeface used to render kanji and kana characters is LXGW WenKai Lite, based on the Klee typeface by Fontworks.

License: SIL Open Font License, Version 1.1
Full license text: https://openfontlicense.org ↗

Key terms: The font may be freely used, embedded, and redistributed with software. It may not be sold on its own. Any modified version must be released under the same OFL 1.1 license.

9. 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.

10. Contact Us

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

support@fillorin.com