Privacy Policy

Effective: August 22, 2026

koshilab ("we", "our", or "us") is committed to protecting the privacy of our users. This Privacy Policy explains how we handle information in connection with our mobile applications.

Information We Collect

Our apps are designed with privacy in mind. We do not collect or store personal information about you, and none of our apps require an account, a login, or any form of registration. One feature — worksheet generation in 漢ドリ (Kanji Drill) — does send the kanji you type to a server in order to work; it is described in full below.

Children's Privacy (COPPA)

Our apps are suitable for users of all ages, including children, and comply with the Children's Online Privacy Protection Act (COPPA). We do not knowingly collect personal information from children under the age of 13. Our apps do not:

• Collect names, email addresses, or other personal information
• Include third-party advertising
• Include social media integration
• Allow users to communicate with other users
• Use analytics that track individual users

Data Storage

All app data — learning progress, saved worksheets, and settings — is stored locally on your device. We do not have access to it, and it is never uploaded to our servers.

Worksheet Generation in 漢ドリ (Kanji Drill)

漢ドリ (Kanji Drill) is the one exception to the sections above, and only for the worksheet generation feature. When you tap to generate a worksheet, the kanji characters you typed are sent over an encrypted connection to our server, which passes them to Anthropic's Claude API to produce example words and test sentences. Only those characters are sent — no name, email, account, device identifier, or advertising identifier is attached.

The words and sentences generated for a given kanji are cached on our server for up to 30 days, so the same character doesn't have to be generated again. The cache is keyed only by the kanji character itself and holds no information about who requested it. Tapping "Regenerate" skips the cache entirely, and its result is not stored.

To stop the service from being abused, our server briefly records the IP address that a request came from, solely to enforce a rate limit. It is used for no other purpose, is never linked to you or to what you typed, is not used for advertising or tracking, and is discarded automatically after an hour. Everything else in 漢ドリ — stroke-order animations, kanji readings, the tracing pages, and your worksheet history — works offline on your device once a kanji has been added.

Third-Party Services

Apart from the Claude API described above, which 漢ドリ (Kanji Drill) uses only to generate worksheet content, our apps do not integrate with third-party services. We use no advertising networks and no per-user analytics. The apps are distributed through the Apple App Store and Google Play Store, each of which has its own privacy policy.

Changes to This Policy

We may update this Privacy Policy from time to time. Any changes will be posted on this page with an updated effective date.

Contact Us

If you have any questions about this Privacy Policy, please reach out through our contact form.