Privacy Policy

MJ Actuary (麻將精算) — Mahjong Scoring Companion

Effective Date: February 9, 2026

This Privacy Policy describes how MJ Actuary ("the App"), developed by Evan Wong ("we", "us", "our"), handles information when you use the App. We are committed to protecting your privacy.

1. Information We Collect

We do not collect any personal information.

The App does not require you to create an account, sign in, or provide any personal details. There is no server, no database, and no analytics tracking operated by us.

2. Data Stored on Your Device

The App stores the following data locally on your device only using the device's built-in storage (SharedPreferences):

Game session data (player nicknames, scores, round history)
App settings (language preference, display preferences)

This data never leaves your device. It is not transmitted to any server, cloud service, or third party. If you uninstall the App, this data is permanently deleted.

3. Third-Party Advertising (Google AdMob)

The App displays advertisements provided by Google AdMob. Google AdMob is a third-party advertising service operated by Google LLC. When serving ads, Google AdMob may collect and process certain information, including:

Device identifiers (e.g., Advertising ID on Android, IDFA on iOS)
IP address
Device information (model, operating system version, screen size)
Ad interaction data (impressions, clicks)
General location data (derived from IP address, not precise GPS)

This data is collected and processed by Google in accordance with Google's Privacy Policy and How Google Uses Information from Sites or Apps That Use Their Services.

We do not have access to the data collected by Google AdMob. We only receive aggregated, anonymous revenue reports (total impressions, clicks, and earnings).

4. App Tracking Transparency (iOS)

On iOS 14.5 and later, the App will request your permission before allowing Google AdMob to track your activity across other companies' apps and websites. You can choose to allow or deny this request. If you deny tracking, you will still see ads, but they may be less relevant to you. You can change this setting at any time in your device's Settings > Privacy > Tracking.

5. Children's Privacy

The App is not directed at children under the age of 13. We do not knowingly collect personal information from children. The ads served in the App are not targeted at children. If you believe a child has used the App and you have concerns, please contact us at the email below.

6. Data Sharing

We do not sell, trade, or share any user data with third parties. The only third-party service integrated into the App is Google AdMob for advertising, as described in Section 3 above.

7. Data Security

Since all game data is stored locally on your device and is never transmitted over the internet by the App, it is protected by your device's built-in security features (device lock, encryption). We recommend keeping your device's operating system up to date.

8. Your Rights

You have the right to:

Delete your data — Uninstall the App to remove all locally stored data, or start a new game within the App to clear the current session
Opt out of ad tracking — On iOS, deny the App Tracking Transparency prompt or go to Settings > Privacy > Tracking. On Android, go to Settings > Google > Ads > Opt out of Ads Personalization
Request information — Contact us to ask about data practices

9. Changes to This Privacy Policy

We may update this Privacy Policy from time to time. Any changes will be posted on this page with an updated "Effective Date" at the top. We encourage you to review this page periodically.

10. Contact Us

If you have any questions or concerns about this Privacy Policy or the App's data practices, please contact us at:

Evan Wong
Email: evanwhl508+mjactuary@gmail.com