Privacy Policy
Short version: we don't collect anything
Last updated: April 10, 2026
The short version
MAHJ is an educational app that teaches American Mahjong. We don't collect your name, email, location, or any other personal information. Your learning progress is saved only on your device and never leaves it. We don't use analytics, tracking, or ad networks. The AI Coach and Hand Analyzer features call third-party AI providers (Anthropic and Google) to generate their responses — see our full privacy policy for what those features send.
What we store
MAHJ stores your lesson progress, quiz scores, and completion timestamps locally on your device using your browser's built-in storage (localStorage). This data never leaves your device and is never sent to us or anyone else.
You can clear this data at any time by tapping the "Reset Progress" button on the home screen, or by clearing your browser's site data.
What we don't collect
- Your name, email, phone number, or any contact information
- Your location
- Your device ID, advertising ID, or any tracking identifiers
- Analytics or usage data
- Contacts, photos, or any data from other apps
Third-party services
MAHJ does not use any third-party analytics, advertising networks, crash reporting services, or tracking tools. The AI Coach (/coach) and Hand Analyzer (/analyze) features send your typed questions or hand state to third-party AI providers (Anthropic and Google) to generate responses. See our full privacy policy for details on what is sent and what is stored.
Children's privacy
MAHJ is safe for all ages. Because we don't collect any data from anyone, we comply with the Children's Online Privacy Protection Act (COPPA) by default.
Changes to this policy
If we ever change this policy, we'll update the date at the top of this page. Since MAHJ doesn't collect data, any changes would only be to clarify how the app continues not to collect data.
Contact
Questions about this policy? Email info@welcome2mahj.com.
Not affiliated with NMJL
MAHJ is an independent educational tool. It is not affiliated with, endorsed by, or sponsored by the National Mah Jongg League® (NMJL®). To play official American Mahjong games, purchase the current year's card from nationalmahjonggleague.org.