Privacy Policy
Last updated: August 5, 2026
In brief: Tanuki stores your learning progress on your device first, so the app is fully usable offline. An anonymous account (a random identifier, with no name, email, or contact information) lets the app back up your progress to Firebase infrastructure operated by Google LLC, and lets you send an optional content report. You can optionally link a Google or Apple account to carry your progress to a new device, and only then do we receive your email address and display name. Tanuki does not sell your data, and Section 6 sets out the diagnostic services the App uses and what the current version does not do. Optional Tanuki Pro purchases are processed entirely by the Apple App Store or Google Play, so we never see or store your payment details.
1. General Information
Tanuki ("the App") is a mobile application that teaches English speakers hiragana, katakana, kanji and the Japanese language, developed and published by IOCODO LLC ("we", "our", "us").
This Privacy Policy explains what information the App handles, how it is used, and the choices available to you. Tanuki is designed to be privacy-first: it is usable offline, and it never requires you to provide a name, email address, or any other personal detail.
2. Data Stored on Your Device
The App stores your learning data locally on your device, in a local database. This is the primary copy of your data and is what makes the App work offline. It includes:
- Your learning progress and spaced-repetition review schedule (which kana, kanji, words and grammar points you have studied and when they are due for review)
- In-app preferences and settings (sound, haptics, reminder time, and similar options)
- Locally scheduled practice reminders, if you choose to enable notifications (these are scheduled on your device by the operating system and are not sent from any server)
This on-device data is removed when you uninstall the App, subject to any device backup behavior controlled by Apple or Google.
3. Account and Authentication
Tanuki does not require you to create an account or sign in to learn. On first launch the App signs you in anonymously using Firebase Authentication (Google LLC), which generates a random identifier tied to your installation. That identifier carries no name, email address, password or phone number, and we cannot identify you personally from it. The anonymous session is what backs up your learning progress and lets you submit a content report.
From Settings you can optionally link that guest session to a Google account or to Sign in with Apple, so your progress follows you to a new device. Linking is never required and no part of the App is locked behind it. If you choose to link:
- We receive your email address and, when the provider supplies it, your display name. Firebase Authentication stores them against your account.
- We never receive your password. You authenticate with Google or Apple, not with us.
- Sign in with Apple lets you hide your real address. If you do, we only ever see Apple's private relay address.
- Your email address and name are used only to identify your account and restore your progress. They are not used for marketing, are not shared with anyone else, and are deleted with everything else when you delete your account (see Section 10).
4. Data Stored in Firebase Backend Services
Tanuki uses a small set of Firebase services operated by Google LLC:
- Firebase Authentication: issues the anonymous identifier described above, and stores your email address and display name if you choose to link a Google or Apple account.
- Cloud Firestore: stores a best-effort backup of your learning progress (your spaced-repetition review data), keyed to your anonymous identifier, so it is not lost if you reinstall the App on the same device. It also stores the content reports described in Section 5. Neither stores your name, email address or contact details.
- Firebase App Check: verifies that requests come from a genuine Tanuki installation, using device attestation (App Attest on iOS, Play Integrity on Android). It does not send us your name, email address or contact details.
- Firebase Remote Config: lets us update small pieces of App configuration remotely, such as the minimum supported App version. It does not send us your name, email address or contact details.
The cloud backup is best-effort: if you are offline, or if background sync is unavailable for any reason, the App keeps working normally from the local copy on your device, which remains the source of truth.
5. Content Reports
If you tap "Something looks wrong?" to report a reading, translation, pitch-accent, or other content error, the App sends us a small report so we can fix it. A report contains only: the item being reported, the type of problem, a short note if you choose to add one, the App version, and your anonymous identifier. It carries no name, email address or contact detail and is used solely to improve the App's content. Reporting is always optional.
6. Analytics and Crash Reporting
The current version of the App integrates no advertising SDK and uses no advertising identifier. If a future version changes that, we update this policy before that version is released, and where the law requires it we ask for your consent first.
The App does use two Google-provided diagnostic services:
- Firebase Analytics: records anonymous usage events (for example, which screen you opened or which level you completed) so we can understand how the App is used and improve it. These events never include your name, email, or any other personally identifying information.
- Firebase Crashlytics: automatically collects crash and error reports if the App malfunctions, including your device model, operating system version, App version, and a technical log of what the App was doing at the time. This helps us find and fix bugs. Crash reports do not include your name, email, or the content of what you were studying.
7. Network Requests and Third-Party Services
During normal operation, the App communicates only with the following third-party services:
- Firebase Authentication (Google LLC): anonymous identifier, plus email address and display name if you link an account
- Google Sign-In (Google LLC): optional account linking
- Sign in with Apple (Apple Inc.): optional account linking
- Cloud Firestore (Google LLC): learning-progress backup and content reports
- Firebase App Check (Google LLC): request integrity verification
- Firebase Remote Config (Google LLC): remote App configuration
- Firebase Analytics (Google LLC): anonymous usage analytics
- Firebase Crashlytics (Google LLC): crash and error diagnostics
- Google Fonts (Google LLC): font assets for this web page only
Important: Each third-party service listed above processes data under its own privacy policy. Please review those policies directly for provider-specific details on data handling and retention.
8. Payments and Subscriptions
Tanuki is free to start. An optional Tanuki Pro upgrade (a monthly or annual auto-renewing subscription, or a one-time lifetime purchase) unlocks the higher JLPT levels. All payments are processed entirely by the Apple App Store or Google Play. We do not operate our own payment system.
We never receive, see, or store your credit-card number, billing address, or any other payment details. The store reports back to the App only whether a valid Tanuki Pro entitlement exists, so the App can unlock paid content. That entitlement check carries no card number, billing address or other payment detail. Your purchases, billing, and refunds are governed by the privacy policy and terms of the store you bought from. See our Terms of Use for the subscription terms.
9. Data Sharing and Sale
We do not sell your data. We do not share your data with any third party except as required to operate the App (specifically, by transmitting your anonymous learning backup, content reports, and diagnostic data to the Firebase services described above) or as required by law. No data is shared with other users.
10. Account Deletion and Data Retention
You can delete your anonymous account and all associated data at any time:
- In-app: open Settings, scroll to the bottom, and tap Delete account, then confirm. This clears all learning data stored on your device, removes your content reports, and deletes your Firebase Authentication identity, including the email address and display name if you had linked a Google or Apple account.
- By email: send a request to support@iocodo.com with the subject "Tanuki Account Deletion". We will complete the deletion within 30 days and confirm by reply.
After deletion, any remaining copy of your data in our backend systems, including the learning-progress backup described in Section 4, is removed within 30 days.
11. Children's Privacy
Tanuki is a general-audience education app. It is not directed at children under the age of 13, and we do not knowingly collect personal information from children. The App can be used in full without an account: nothing in it requires a name, an email address or any other personal detail, so it is suitable for learners of all ages under the supervision appropriate to their context. The optional account linking described in Section 3 is a choice made by the device owner.
12. Your Rights (GDPR, CCPA and similar laws)
Depending on where you live, you may have rights over your data under laws such as the EU/UK General Data Protection Regulation or the California Consumer Privacy Act. Unless you have linked a Google or Apple account as described in Section 3, the only data we hold about you is the anonymous learning data described above, so that is what most of these rights apply to. You can, at any time and without needing to prove your identity beyond having the App installed:
- Access or export your learning data, by using the in-app export or review features where available, or by contacting us.
- Delete your data and anonymous account, as described in Section 10.
- Object to or restrict the anonymous backup and analytics described above, by using the App fully offline and declining optional features such as content reporting.
- Contact us with any question or request about your data, at the email address in Section 14.
We do not sell personal information and there is no "sale" or "sharing" of data to opt out of under the CCPA.
13. Changes to This Policy
We may update this Privacy Policy from time to time. If we make material changes, we will update the "Last updated" date at the top of this page. Continued use of the App after changes are posted constitutes your acceptance of the updated policy.
14. Contact
If you have questions about this Privacy Policy, please contact:
IOCODO LLC
Email: support@iocodo.com
Website: iocodo.com