Privacy policy
Effective 7 October 2026
KanjiLock is a Japanese vocabulary app for Android. It has no user accounts and no servers of its own. This page covers the app and this website.
The short version
- Your words, decks and progress stay on your phone.
- No ads, no analytics, no tracking, no selling data.
- Google Drive sync is optional and goes to your own Drive. The developer never gets a copy.
This website
This website has no cookies, no analytics and no ad or tracking scripts. Fonts and images are served from this site, not from Google or any other font service.
The site is hosted on GitHub Pages. Like any web host, GitHub may log technical data such as your IP address when you visit, under the GitHub Privacy Statement. The download links go to GitHub, which handles the download the same way.
The quiz on the home page runs in your browser. Your answers are not saved or sent anywhere.
Data the app stores on your phone
The app keeps these only in its private storage on your device:
- words you keep, reject or add yourself
- decks you import and your review history for them
- daily activity for the streak calendar
- app settings
None of this is sent to the developer.
Google Drive sync (optional)
If you link Google Drive:
- The app asks for the
drive.filepermission. It can only see files it created or that you open with it, not the rest of your Drive. - It creates a folder called KanjiLock with one file,
kanjilock-data.json, holding the data listed above. - The file goes straight between your phone and Google over HTTPS. The developer never receives it.
- You can unlink Drive in Settings at any time. Delete Drive copy removes the folder and file. You can also remove the app's access at myaccount.google.com/permissions.
KanjiLock's use and transfer of information received from Google APIs adheres to the Google API Services User Data Policy, including the Limited Use requirements. Drive data is only used for the sync you turned on. It is not used for ads, not sold, not shared and not read by people.
AnkiDroid (optional)
If you connect AnkiDroid and grant its database permission, the app reads your deck names and cards from AnkiDroid on the same phone and sends your review answers back to it. This stays on your device. AnkiDroid's own sync with AnkiWeb follows AnkiDroid's and AnkiWeb's policies.
Other features that touch the network or your phone
- Draw to search uses Google ML Kit Digital Ink Recognition. The first time you open it, the app downloads the Japanese handwriting model from Google. After that, your drawing is read on the phone and not uploaded. Like other Google Play services components, ML Kit may send Google basic diagnostic and usage data about the library itself, as described in the ML Kit terms.
- Updates. The GitHub version checks api.github.com for a newer release when it opens, at most every 6 hours, and only downloads a new APK when you tap Update. GitHub sees these requests like any web visit, including your IP address. You can turn this off in Settings, Updates.
- Text to speech uses the speech engine already installed on your phone.
- Notifications and reminders are made on your device.
- Exports and backups (CSV, Anki text, .apkg, backup files) only go where you send them.
What the app does not do
No ads, no analytics or crash reporting of its own (the ML Kit note above is the only exception), no tracking, no location, no contacts, no selling or sharing of data. If the app crashes, the crash report is saved on your phone and only leaves it if you copy or share it yourself.
Children
KanjiLock is not directed at children under 13. The built-in dictionary is a general Japanese dictionary and includes adult vocabulary.
Deleting your data
- Clear the app's storage in Android settings, or uninstall it, to remove everything on your phone.
- Use Delete Drive copy in Settings, or delete the KanjiLock folder in Google Drive, to remove the synced copy.
Changes
If this policy changes, the new version goes on this page with a new date.
Contact
Questions about privacy: open an issue on GitHub.