Mojiya — Privacy Policy

Last updated: 26 September 2026.

Mojiya ("the app") is a Japanese-learning app published by Mojiya Studio. This policy explains what the app does and does not do with your information.

The short version

The app shows no ads and uses no analytics or trackers. Everything you do — your lessons, reviews and settings — is stored on your device. You can use the free lessons without an account. If you buy the course, you sign in with Google, and we keep a record that your account owns the course so we can release the course download to you on any of your devices.

What is stored, and where

• Your study data stays on your device. Your review history, progress, settings, and any books, subtitles or dictionaries you import are stored on your device. The app does not send them to us.
• Device backup (optional). If Android's backup is on, Android may include the app's progress database in the backup to your own Google account, so it can be restored on a new device. Google handles that backup under its own terms, and we never see it.
• Files you import stay on your device unless you ask otherwise. The reader and player read books, video and subtitle files locally, and do not send them to us.
  • If you turn on a library-backup switch in Settings and choose a folder (for example in Google Drive or iCloud Drive), the app copies the files you chose into that folder.
  • Your cloud provider then stores them under its own terms, on your quota, and we never see them.
  • Turning the switch off stops future copies.

If you buy the course: your account

• What we store. When you sign in, we store an account identifier; the identifier Google gives us for your Google account; your email address, if Google provides it; and a record of which course licence the account holds and until when. We use these only to recognise you and to release the paid course download to your account. We do not use them for marketing.
• Purchases. Google Play processes purchases of the course subscription, the lifetime unlock and optional supporter tips. We do not receive your payment details. Purchase records are managed for us by RevenueCat, a subscription service that acts as our processor. RevenueCat receives your account identifier and the purchase records Google provides, and tells us whether your account currently owns the course.
• The course download. Downloading the course sends your account identifier to our server so it can check your licence. The download itself comes from our storage provider (Cloudflare) through a link that expires, and your device's IP address is visible to them for that request.
• Deleting your account. You can delete your account in the app (Settings → Account → Delete account) or as described at mojiya.app/delete-account.
  • Deleting it removes the account, its sign-in link and its licence record from our server, and asks RevenueCat to delete its record of the account.
  • Your study data on your device is not affected.
  • Google Play keeps its own record of your purchase under Google's terms.

When the app uses the internet

The free lessons work fully offline. The app goes online only for these:

• Download on a recommended dictionary in Settings fetches that dictionary directly from its publisher's website.
• Opening the purchase screen asks Google Play and RevenueCat for the prices in your currency. RevenueCat then holds an anonymous identifier for this install, and no personal information.
• Signing in, buying, and the course download talk to Google, RevenueCat and our server as described above.

As with opening any web link, your device's IP address is visible to the server you reach. The app adds no tracking to these requests.

What the app does not do

• No advertising, and no advertising identifiers.
• No third-party analytics or tracking SDKs.
• No selling or sharing of personal data.
• No account unless you buy the course.

Security

Account traffic is encrypted in transit (HTTPS). Your sign-in token is stored in your device's encrypted keystore.

Children

The app is a general-audience learning tool and is not directed at children under 13.

Changes

When cloud sync is turned on, we will update this policy before that release, to describe the study data the server then stores.

Contact

Questions about this policy: support@mojiya.app.