Sumo Kanji

Privacy Policy

Last updated: 4 November 2026

Sumo Kanji (“we”, “us”) is an app for learning Japanese on iPhone, iPad and Mac, made by Anatolii Kataev, an individual developer in Yerevan, Armenia. In short: Sumo Kanji has no accounts and no server of ours. What you learn and how you set the app up stay on your device. The one company the app talks to is RevenueCat, to check your subscription. This policy explains the details. Questions: support@sumojapanese.app.

What stays on your device

  • Your learning: the pages of your notebooks you have written and when, your homework and test sheets with your answers (the readings you typed and the characters you wrote by hand) and their marks, your stamp card, and your review schedule.
  • Your settings: where you start in the course, your pages a day, whether you want romaji, reminder time, sound and display choices.
  • All of this is kept only in the app’s storage on your device. It is never sent to us - we have no server, no accounts and no way to see it. Deleting the app deletes it.
  • If your device backs up apps (iCloud Backup, for example), the backup may include this data. It stays under your own Apple Account and settings; we can’t see it.

Subscriptions: what RevenueCat receives

  • Apple’s App Store handles payment for Sumo Kanji Pro. We never receive your card details, your name or your email address.
  • RevenueCat (RevenueCat, Inc.) confirms your subscription for us. To do that, the app sends RevenueCat a random identifier made on your device (not linked to your name or to any account), your App Store purchase records, and basic technical details: the kind of device, its operating system and app version, and your store’s country and currency. Like any internet service, RevenueCat’s servers also see the IP address the request comes from.
  • We use this only to unlock Sumo Kanji Pro, restore it on a new device and know how many people subscribe. RevenueCat processes it on our instructions; its privacy policy is at revenuecat.com/privacy.

Reminders

If you turn on daily reminders, they are scheduled on your device by its own notification system. No push service is used and nothing about them leaves your device. Turn them off in the app or in your device settings at any time.

The course and its voice

Every lesson, kanji, word, sentence and voice recording is part of the app. Nothing is downloaded while you learn, and Sumo Kanji never uses your microphone or camera.

What we don’t do

  • No advertising and no ad networks.
  • No analytics, no crash-reporting service and no tracking across other companies’ apps or websites.
  • We don’t sell or share personal data - we don’t collect any beyond the subscription details above.

Children

Sumo Kanji doesn’t ask for or collect personal data from anyone, children included. Purchases on a child’s device follow Apple’s family and parental controls.

Your choices and rights

  • Reset your progress in the app (Settings → About → Reset progress), or delete the app to remove everything it stored.
  • Manage or cancel Sumo Kanji Pro in your Apple Account’s subscription settings; restore it in Settings → Subscription.
  • Ask about the subscription details RevenueCat holds for your device, or for them to be deleted, by writing to support@sumojapanese.app (we will need the identifier shown in Settings → Subscription). Depending on where you live (for example the EU, the UK or California) you may also have the right to object to processing and to complain to your data-protection authority.

International transfers

RevenueCat may process subscription details outside your country, under safeguards such as the EU Standard Contractual Clauses where they are required.

Changes

If we change this policy we will update the date above, and tell you in the app before significant changes take effect.

Contact

Sumo Kanji is made by Anatolii Kataev, an individual developer in Yerevan, Armenia. Email support@sumojapanese.app with any question about your privacy.