Privacy Policy

This Privacy Policy explains what information the Hong Kong Mahjong app ("the App," "we," "us") collects, how it is used, and the choices you have. Hong Kong Mahjong is a single-player game — you play against computer (AI) opponents only. There is no multiplayer, no chat, and we never connect you to other real players.

Summary

• You can play the entire game without an account and without giving us any personal information. In that mode everything stays on your device.
• If you sign in (with Google or Apple), we receive a minimal account record used to authenticate you. Your gameplay profile, statistics, history, and learning progress stay on this device.
• We do not sell your data, show third-party ads, or track you across other apps and websites.

Information we collect

1. Information stored only on your device

Whether or not you sign in, the following is kept in local storage on your device and is not sent to us:

• Your display name and chosen avatar
• Gameplay statistics (hands played/won, faan, self-draws, deal-ins, training accuracy, achievements, and recent hand history)
• Your selected tile theme and app settings
• Records of purchases/entitlements (which tools you own; Plus status)

2. Information collected if you create an account

When you sign in with Google or Apple, we receive and store:

• A unique account identifier
• Your display name and (if provided) avatar/photo reference
• The email address associated with the sign-in (used only to identify your account; we do not email you marketing)

We use a third-party authentication provider (Google Firebase Authentication) to handle sign-in. We never receive or store your Google or Apple password.

3. Purchase information

In-app purchases and the Plus subscription are processed by the Apple App Store, and validated through our payments provider (RevenueCat). We receive a record of what you purchased and your entitlement status. We do not receive or store your credit-card or full payment details — those are handled entirely by Apple and RevenueCat.

4. Anonymous usage statistics

We collect anonymous usage events — such as when a hand starts or ends, or when the store is opened — through Mixpanel, our analytics provider. These events are tied to a random device identifier, never to your name or email address, and are used solely to understand how the App is played and to improve it. They are not used for advertising and not shared with data brokers, and on the web version we honor your browser’s “Do Not Track” and “Global Privacy Control” signals.

How we use information

• To authenticate your optional account
• To unlock the features and cosmetics you have purchased
• To operate, maintain, and improve the App
• To detect and prevent fraud or abuse

We do not use your information for advertising or sell it to third parties.

Third-party services

The App relies on these processors, each under their own privacy policy:

• Google Firebase Authentication — optional account sign-in
• Apple — Sign in with Apple and App Store purchases
• Google — Sign in with Google (authentication only)
• RevenueCat — purchase/subscription validation
• Mixpanel — anonymous usage analytics

Data retention and deletion

Local data is removed when you uninstall the App or clear its storage. If you have an account and want its authentication record deleted, use the Delete account option in the App's account screen, or contact us at the email below. The in-app action also resets the profile, statistics, history, and learning progress stored on that device.

Children's privacy

The App is not directed to children under 13 (or the minimum age required in your country). We do not knowingly collect personal information from children. The App contains no real-money gambling — in-game scoring uses points with no cash value.

Your choices

• Play without signing in to keep all data on-device.
• Sign out at any time from the account screen.
• Delete your account and data at any time from the account screen, or via the contact email.
• Manage or cancel the Plus subscription through your App Store account settings.

Changes to this policy

We may update this policy from time to time. Material changes will be noted in the App and by updating the "Last updated" date above.

Contact

Questions or data requests: andrew@revenuearc.com