Kotoba Privacy Policy
Last updated: 23 August 2026
Supermassive (“we”, “us”) operates the Kotoba app (package name kr.supermassive.kotoba). Kotoba is a JLPT vocabulary learning app. You can use it without creating an account. This policy explains what information is processed when you use Kotoba, and how to contact us.
1. Purpose of processing
We process information only to:
- Provide learning, review, quizzes, progress, and settings on your device
- Send study reminders you choose to enable
- Show ads
- Restore learning data through Android backup if you have Google backup turned on
- Respond if you contact us about privacy
We do not use this information for other purposes.
2. Information we process
Stored on your device. Learning progress, word status, streaks, XP, achievements, daily goal, target level, app language, theme, speech settings, and reminder time stay on your device. Supermassive does not operate a user-account server and does not collect this learning data from the app.
Android backup. If Google backup is enabled on your device, the learning database and settings may be backed up to your Google account and restored after reinstall. Firebase Cloud Messaging registration is excluded from backup. Restore is handled by Google, not by a Supermassive server. This is not real-time sync across devices.
Notifications. Local study reminders are scheduled on your device after you allow notifications. If Firebase Cloud Messaging is used, Google may create a device token so a message can be delivered. Firebase auto-initialization is off by default.
Advertising (Google AdMob). Kotoba shows an app-opening ad and an ad on the exit confirmation dialog. There is no always-on banner above the tab bar. In regions that require consent (including the EEA and UK), Google’s User Messaging Platform is shown before the ads SDK is initialized. Where required, you can manage ad privacy options in Settings. Google may process advertising identifiers, device and app information, IP address, approximate location, and ad interaction data under Google’s policies.
Other. Open-source license text may be loaded from GitHub when you open the license screen. Pronunciation uses the device text-to-speech engine.
3. Third parties
We do not sell your personal information. We do not share learning records with other companies for their own marketing. The following Google services may process data as independent controllers or processors, according to their policies:
- Google AdMob and the Google User Messaging Platform
- Firebase Cloud Messaging
- Google Play services and Android backup
Google’s privacy policy: https://policies.google.com/privacy
Google advertising: https://policies.google.com/technologies/ads
4. Retention
- On-device learning data: until you reset data in Settings or uninstall the app
- Android backup: according to your Google account and device backup settings
- Ads and messaging: according to Google’s retention policies
- Email you send us: until the request is resolved
5. Your rights
Depending on where you live, you may have rights to access, correct, delete, or restrict processing of personal information, and to withdraw consent. You can delete on-device learning data with Reset all data in Settings. For other requests, email [email protected]. We may need to confirm that the request comes from you.
6. Age rating and children
Kotoba’s IARC content rating is 3+ / Everyone. The app does not require an account, and learning data stays on the device. We do not collect more personal information from children than this policy describes. A parent or guardian can email us to ask for deletion.
7. International transfers
Google’s services may process information outside your country, including in the United States. Those transfers follow Google’s terms and applicable law.
8. Security
Learning data is kept on the device. Ads, messaging, and backup use Google’s infrastructure. No method of storage or transmission is completely secure.
9. Contact
Privacy officer: Supermassive
Email: [email protected]
10. Changes
We will post updates to this page. If a change is material, we will provide notice at least 7 days before it takes effect where required. This policy applies from 23 August 2026.