Privacy Policy

Yomuki: Read Japanese, published by DexGrid B.V.

Yomuki is designed to collect as little data as possible. There are no ads, no third-party advertising SDKs and no trackers. Your learning progress is the only personal data that exists, and you can delete it at any time from within the app or via our account deletion page.

What we collect

Account data (only if you sign in)

• Your email address, via Firebase Authentication — used only to create and identify your account. If you sign in with Google, Google shares your email address and name with the app. Your email address is never stored in our learning database; only your anonymous account ID is.
• If you choose not to sign in, the app works fully offline and no account is created.

Learning data (only while signed in)

• Your answers during study sessions (which item, whether it was correct, when you answered) and your settings (new items per day, audio autoplay, reminder on/off, reminder time).
• These sync across your devices through Firebase Firestore when you are online, so your progress is available on each device. Your learning data is stored locally on each device (SQLite) and in the cloud only while your account exists.

Usage analytics and crash reports (only with your explicit consent)

• Firebase Analytics receives anonymous usage events (for example: a session started, an item was answered) — never the content of your answers.
• Firebase Crashlytics receives crash reports. App errors carry only the error category and code location; they never contain your learning data or personal information. Native crashes are limited to what the operating system provides.
• Both are off by default and start only after you opt in during onboarding or in Settings. You can withdraw consent at any moment, and events stop immediately. Your choice is forgotten when your account is deleted.

What we never do

• No advertising, no ad SDKs, no sale or sharing of data with third parties for marketing.
• No profiling: analytics events measure feature usage only.
• No access to your Google account beyond your email address and name.
• No data collection for children-specific targeting.

Where data lives and how it is protected

• Learning data and account data are stored in Google Firebase (Google Cloud), encrypted in transit (TLS) and at rest by Google’s default infrastructure protection.
• Access to your learning documents is technically restricted by server-side security rules so that only a signed-in account can reach its own documents; nobody else, including other users, can read or write them.
• Yomuki is excluded from Android cloud backup and device-to-device transfer: your learning data stays on your devices and your account, never in Google’s device backups.

Retention and deletion

• Learning data is kept while your account exists.
• You can delete your account and all synced learning data at any time in Settings → Delete account, or without the app via our account deletion page. Deletion removes your sign-in account, your answers and your settings from the cloud, and the app asks whether to also wipe the local data on the device you are using.
• After deletion we keep one minimal record: your anonymous account ID and the deletion timestamp, so that a second device of yours can detect the deletion and so the deleted account cannot be written to again. It contains no email address, name or learning data.
• Analytics and crash data are retained by Firebase according to its standard retention settings and are linked only to an anonymous app instance ID, not to your account.

Children

Yomuki is not directed at children under 13, and we do not knowingly collect data from children under 13.

Your rights (GDPR)

You may request access, correction, export or deletion of your data via privacy@dexgrid.nl (or the address on our deletion page). Since we store almost no personal data beyond your learning progress, the in-app deletion fulfils most requests directly.

Changes

We will update this page if Yomuki’s data handling changes and adjust the in-app consent flow when new data use is introduced.

Contact

DexGrid B.V., Netherlands — privacy@dexgrid.nl