Kana Override – Privacy Policy
Last updated: 6 November 2026
The short version: the Kana Override app does not collect, store on a server, share or sell any personal data. Everything the app knows stays on your phone. There are no accounts, no ads, no analytics and no tracking. The only personal data I hold is an email address, and only if you choose to sign up on this website to test the app (see "Signing up to test" below). The app doesn't use the internet today. If it gains language updates, those requests would include a few technical details (see "Internet access, third parties and tracking" below).
Who I am
Kana Override is made by mikevdv (mikevdv.dev), an independent developer. If you have any questions about this policy, you can contact me on Bluesky: @mikevdv.dev.
What the app does
Kana Override helps you practise a language, such as Japanese. When you use apps you have chosen (for example a social media app), it interrupts you every so often with a short quiz. To do that it needs to know which app is open and for how long.
What the app uses, and where it stays
All of this is kept on your device and isn't sent anywhere. The one possible exception in future is that a language update could say which language it's asking for (see "Internet access, third parties and tracking" below).
| What | Why | Where it lives |
|---|---|---|
The name of the app currently in front (its package name, such as com.example.app) | To know when you are in one of your chosen apps, and to count the time you spend there | Held in your phone's memory while the app runs. It is not logged or kept as a history |
| The apps you choose to be quizzed in | So the app knows which apps to interrupt | In the app's private storage on your phone |
| A list of the apps installed on your phone (their names and package names) | To let you pick which apps to include | Read when you open the app picker, and only the apps you pick are saved |
| Your settings (how often to quiz, what you are learning, how you answer, sound on or off) | So the app behaves the way you set it up | In the app's private storage on your phone |
| Your quiz progress (how you are doing on each character, and your personal best times) | To show characters you find hard more often, and to show your best times | In the app's private storage on your phone. The answers you type are checked and then discarded; they are not saved |
| How long you spend in quizzes (a total for each week, and an all-time total) | To show your study time on the Home screen, and in an optional notification on Mondays comparing last week with this one | In the app's private storage on your phone. The notification is made on your phone and is only sent if you switch it on, after you allow notifications |
| Which languages your enabled keyboards support | To offer typing answers in a language's own writing (such as kana or Chinese characters) only if you have a keyboard for it | Checked on your phone when needed, never stored. The app never sees what you type in any other app |
The Accessibility Service
Kana Override uses Android's Accessibility Service. You turn it on yourself in your phone's settings, and the app guides you through this the first time you use it.
- What it is used for: only to find out which app is in the foreground, so the app can time your use of the apps you chose and show a quiz at the right moment.
- What it reads: the code reads only the package name of the app that an event came from. It does not read, store or send the text, content or fields on your screen, and it does not see what you type, your messages, passwords or anything else in other apps.
- What it does not do: the service is set up without requesting access to window content. It does not control your phone, make purchases, or perform actions on your behalf.
- Where the information goes: nowhere. It is used on the spot and not transmitted, shared or sold.
- Turning it off: go to Settings → Accessibility on your phone and switch off Kana Override. The app will keep working as a normal app but will no longer interrupt you in other apps, and it will remind you that the service is off.
Notifications
Kana Override can send you one notification a week, on Monday at about 11:00, saying how long you spent in quizzes last week. It is off until you switch on Weekly Summary in Settings, and on Android 13 and later the app asks your permission to show notifications at that point. If you say no, nothing is sent.
- How it works: the text is made on your phone from the quiz time the app has stored. It is not sent to or from any server, and no push service is involved. The app sets an alarm on your phone for the next Monday.
- Why the app asks to know when the phone restarts: an alarm is cleared when the phone restarts, so the app uses Android's boot-completed signal to set it again. It does nothing else with it.
- Turning it off: switch off Weekly Summary in Settings, or turn off the app's notifications in your phone's settings.
Internet access, third parties and tracking
- Today, Kana Override does not send data over the internet or connect to any server of mine or anyone else's.
- Language updates in future: I may add a way for the app to download new or updated language content without a full app update. Each download would be a request to a server, so it would have to include some technical details, such as your IP address, the app's version, the type of phone and which language it's asking for. It would not include your quiz progress, the apps you chose, the name of the app in front or anything you type. If I add this, I will update this policy before it reaches you.
- It contains no advertising, no analytics, no crash-reporting service and no third-party code that collects data.
- The artwork in the app (illustrations from unDraw) is included in the app itself. The app does not load anything from unDraw or any other website.
Backups
Android's built-in backup may be turned on for your phone. If it is, Google may back up Kana Override's saved data (your settings, the apps you chose, your progress and your study time) to your Google Account, in the same way it does for other apps. That is controlled by your phone and Google's own policies. I never receive or have access to it. You can turn it off in your phone's backup settings.
This website
This policy also covers this website, kana.mikevdv.dev. It has no ads, no analytics and no cookies. Like most websites, the server it runs on may keep standard logs for a short time, such as IP addresses and the pages requested, to keep the site running.
Signing up to test
You don't need to sign up to use the app. If you do use the sign-up form on this website:
- What I keep: the email address you enter.
- Why: you've asked me to, so that I can send you information about testing the app and add that address to the Google Play testers list. I don't use it for anything else.
- Who sees it: me, any service I use to store the list or send the emails, and Google once you're on the testers list. Google handles that under its own privacy policy. I don't sell it or share it with anyone else.
- How long I keep it: until testing ends, or until you ask me to remove it, whichever comes first.
- Removing it: message me on Bluesky with the address and I'll delete it and take you off the testers list.
Keeping your data, and removing it
The app's data is on your phone, so you control it. To remove everything the app has saved, go to Settings → Apps → Kana Override → Storage and choose Clear storage, or uninstall the app. The app doesn't send me any of it, so there is nothing on my side to delete or send you. If you signed up to test, see "Signing up to test" above.
Children
Kana Override is not aimed at children, and the app collects no personal data from anyone. The sign-up form isn't meant for children either. If a child has signed up, message me and I'll delete the address.
Changes to this policy
If the app or this website changes in a way that affects your privacy, I will update this page and the date at the top before the change reaches you. The latest version is always on this page.
Contact
Questions or concerns about privacy: message me on Bluesky at @mikevdv.dev. Please use a direct message, and avoid posting personal details in public posts. The app doesn't collect any personal data, so you shouldn't need to send me any, other than the email address you signed up with if you'd like it removed.