Privacy Policy

Effective Date: January 1, 2025

Kyusung Lee ("Developer") operates the Sudoku mobile application ("App"). This Privacy Policy explains what information the App collects, how it is used, and your rights regarding that information.

1. Information We Collect

The App may collect the following information:

Device information: Device model, operating system version, and app version for crash reporting purposes.
App usage data: Screen views, feature usage patterns, and session duration collected anonymously via Firebase Analytics.
Crash reports: Technical error data collected via Firebase Crashlytics to help us improve app stability.
Game data: Your puzzle progress, statistics, and settings are stored locally on your device only and are not uploaded to our servers.
Anonymous user ID: An anonymous identifier (uid) generated via Firebase Authentication, stored on our servers (Firebase/Cloud Firestore) to recognize your device and provide features such as feedback replies.
Push notification token: A Firebase Cloud Messaging (FCM) token used to deliver push notifications (e.g., replies to your feedback), stored on our servers (Cloud Firestore).
Feedback content: When you submit an inquiry or suggestion, the title and content you enter are stored on our servers (Cloud Firestore) so we can review and respond.
Error and crash logs: When an error occurs, technical details (error type, error message, device information, and app version) are stored on our servers (Cloud Firestore) to help us diagnose and fix problems.

2. How We Use Your Information

To identify and fix crashes and bugs (Crashlytics)
To understand how the App is used and improve the experience (Analytics)
To serve relevant advertisements (Google AdMob)

3. Third-Party Services

The App uses the following third-party services:

Firebase Analytics (Google): Anonymous usage analytics. Data retained up to 14 months per Google policy.
Firebase Crashlytics (Google): Crash and error reporting. Data retained per Google policy.
Google AdMob: In-app advertising. Google may use advertising identifiers (IDFA/GAID) for ad personalization.

Each third-party service has its own privacy policy. We encourage you to review them: Google Privacy Policy .

4. Data Storage

Your game data (puzzle state, statistics, and settings) is stored locally on your device using your device's storage, and this game data is not uploaded to any server. Uninstalling the App will delete all locally stored game data.

Separately, certain data is stored on our servers (Firebase/Cloud Firestore): your anonymous user ID (uid), your push notification (FCM) token, any feedback you submit (title and content), and error/crash logs (error type, error message, device information, and app version). This server-stored data is retained per Google's Firebase data retention policies and is used only to operate and improve the App.

5. Children's Privacy

The App is not directed at children under 13. We do not knowingly collect personal information from children under 13. If you believe a child has provided personal information, please contact us and we will delete it.

6. Your Rights

Depending on your location, you may have the right to access, correct, or delete your personal information. Since game data is stored locally on your device, you can delete it at any time by uninstalling the App or clearing app data in your device settings.

For analytics data held by Google, you can opt out of analytics tracking through your device settings (Limit Ad Tracking on iOS / Opt out of Ads Personalization on Android).

7. Changes to This Policy

We may update this Privacy Policy from time to time. Changes will be posted on this page with an updated effective date. Continued use of the App after changes constitutes acceptance of the updated policy.

Appendix. Website Cookies and Visit Analytics

Unlike the other sections, which describe the app, this section applies only to the website (the domain serving this page).

What we collect — pages visited, referral information (UTM parameters), approximate location (country and city level), device and browser type, screen size, and whether a store link was clicked. The identifier stored in cookies is a browser-level online identifier and may qualify as personal information; however, we do not collect your name, email address, phone number, or any other directly identifying information, and we do not use this identifier to single out any individual.
Why we collect it — solely to understand how visitors reach this site so that we can improve it. It is never used for advertising or profiling.
Tool and cookies — Google Analytics 4 (Google LLC), which stores cookies (_ga, _ga_*) in your browser to distinguish browsers. These cookies last for up to 2 years, and you can delete them at any time using your browser's cookie controls.
Retention — Google Analytics event data is retained for up to 14 months and then deleted automatically. Your consent choice and referral values are stored only in your own browser and are never sent to our servers.
Outsourced processing and international transfer — the statistics above are processed by a processor acting within the scope of our instructions, which constitutes an overseas transfer for outsourced processing; the following is disclosed under Article 28-8 of the Korean Personal Information Protection Act. Recipient: Google LLC (1600 Amphitheatre Parkway, Mountain View, CA, USA; contact via the Google Privacy Policy). Country of transfer: the United States. Timing and method of transfer: transmitted over the network via cookies from time to time as you use the website. Items transferred: as listed under "What we collect" above. Recipient's purpose of use: generating and analyzing visit statistics for this website, within the scope of our instructions. Recipient's retention period: as stated under "Retention" above. You may refuse this transfer as described under "How to consent, refuse, or withdraw" below, with no disadvantage whatsoever in using the website. We do not provide the data to any other third party.
How to consent, refuse, or withdraw — choose Decline on the banner shown on your first visit and Google Analytics is never loaded; the site remains fully usable. Even after accepting, you can withdraw your consent at any time via Cookie settings; when you withdraw (decline), the related cookies are deleted. As an additional option, you can also remove the cookies by clearing cookies and site data in your browser.

The referral tags (UTM) appended to store buttons do not identify you, are held only for the current browser session, and work regardless of your cookie choice.

8. Contact

Developer: Kyusung Lee (이규성)

App Name: Sudoku

Email: contact@leekyusung.kr