Privacy Policy

Last updated: August 14, 2026

This policy covers the Android version of Kotomaji, distributed through Google Play. The iOS version is covered by a separate policy, because it contains no analytics at all.

This Privacy Policy applies to the Kotomaji Android app, published by Quantum Quacks (referred to as "we", "us" or "our") and distributed through the Google Play Store.

1. Data controller

2. Summary

Kotomaji does not ask you for any personal data. There is no account, no sign-in, and no advertising. Your in-app data — such as favorites and settings — is stored only on your device and is never sent to us.

The app does collect anonymous usage statistics so we can see which features people actually use and improve them. These statistics are not linked to your identity, and we never collect your advertising ID. Section 5 explains exactly what is measured.

3. Data stored on your device

The following data is kept locally on your device and is never transmitted to our servers:

  • Your favorite phrases and kanji.
  • App preferences (interface language, audio settings, preferred currency).
  • Your Kotomaji Pro purchase status.

This data is removed when you uninstall the app or clear its storage.

4. Network use

The optional currency converter fetches up-to-date exchange rates from a public rates provider. These requests contain no personal data and are not tied to your identity. If you have no connection, the converter falls back to the most recent rates stored on your device. Everything else in the app — phrases, audio, kanji and tips — works fully offline. The other uses of the network are the anonymous usage statistics described in section 5 and in-app purchases through Google Play.

5. Anonymous usage statistics

Kotomaji uses Google Analytics for Firebase to understand how the app is used, so we can decide what to build and fix next. What is measured:

  • Which features you use and when — for example that a phrase was played, a favorite was added, the converter was used, or the Pro screen was opened.
  • Whether a purchase completed, and its price and currency.
  • Basic technical information: app version, device model, operating system version, language, and the country your connection appears to come from.
  • A randomly generated app instance identifier. It identifies the installation, not you, and it is reset if you reinstall the app or clear its storage.

Just as importantly, what is not collected:

  • No advertising ID. Kotomaji is available to children, so the app explicitly removes the Android advertising ID permission and disables ad-personalisation signals.
  • No name, email address, phone number or account of any kind.
  • No precise location, contacts, photos, files, microphone or camera access.
  • The words you search for and the content you view are not recorded.

These statistics are never sold, and they are not used to show you advertising or to build an advertising profile. Google processes this data on our behalf as our service provider, under the Firebase Privacy and Security terms.

6. Purchases (Kotomaji Pro)

Kotomaji Pro is a one-time in-app purchase processed by Google Play Billing. We never receive or store your payment details. Google processes the transaction and shares only the information needed to confirm the purchase and to let you restore it on your devices. Google's handling of payment data is governed by the Google Privacy Policy.

7. Permissions

Kotomaji requests only the permissions it needs to function:

  • Internet access: used to retrieve live currency exchange rates, to send the anonymous usage statistics described in section 5, and to complete in-app purchases through Google Play.
  • Notifications: used only for the daily phrase, daily kanji and weekly tip reminders, if you turn them on. You can turn them off at any time in Settings.

Kotomaji does not access your contacts, camera, microphone, location, photos, or files, and it does not request the Android advertising ID.

8. Third-party services

We rely on the following services to distribute the app, process purchases and measure usage:

We do not integrate advertising networks or social media trackers, and we do not sell or share your data with data brokers.

9. Children

Kotomaji is suitable for all ages and we do not knowingly collect personal data from anyone, including children. Because the app is available to children, we comply with the Google Play Families Policy: Kotomaji shows no advertising, does not collect the Android advertising ID, and does not use the statistics in section 5 for ad targeting or personalisation. If you believe a child has provided us with personal data, contact us and we will delete it.

10. Your rights

We hold no information that identifies you — no account, name or email address — so in most cases there is nothing for us to look up. The anonymous usage statistics in section 5 are tied to a random app instance identifier rather than to you.

You can remove all locally stored data at any time by clearing the app's storage or uninstalling it, which also resets the app instance identifier so past statistics can no longer be connected to your new installation. If you want the statistics associated with an installation deleted, or you have questions about your rights under the GDPR or other applicable law, contact us at the email below and we will help.

11. Changes to this policy

We may update this policy to reflect legal, technical, or service changes. The current version will always be published at this URL, with an updated "Last updated" date.

12. Contact

If you have any questions about this Privacy Policy, contact us at contacto@quantumquacks.es.