Privacy Policy

This Privacy Policy explains how Sudoku Knacker ("we", "us", or "our") handles information when you visit sudokuknacker.com (the "Site"). The short version: our tools run entirely in your browser, we operate no user accounts, and we collect no personal data of our own. The details below cover the few things that do happen on this Site.

1. Information We Collect

We do not collect, store, or transmit personal information. The Site has no user accounts, no sign-up forms, and no server-side puzzle processing.

• Puzzle data. The digits you type into the solver, and the photos you use with photo recognition, are processed entirely on your device. They are never uploaded to any server controlled by us.
• Game progress. If you play a puzzle, your progress (grid contents, timer, mistake count) is saved in your browser's local storage so you can close the tab and continue later. This data never leaves your device and is deleted when you clear your browser data.
• Preferences. Your light/dark theme choice and your response to our cookie notice are likewise stored only in your browser's local storage.

2. Cookies and Local Storage

The Site itself uses no tracking cookies. We use browser local storage — a technology similar to cookies but accessible only by this Site in your own browser — for two purposes:

• sk-theme — remembers whether you prefer the light or dark theme.
• sk-consent — remembers your choice on the cookie notice banner.

You can remove this data at any time via your browser settings ("Clear browsing data"). Doing so will not affect the functionality of the Site beyond resetting your preferences.

3. Advertising and Google AdSense

The Site is free because it is supported by advertising. We may display ads served by Google AdSense. Third-party vendors, including Google, use cookies (such as the Google DoubleClick DART cookie) to serve ads based on your prior visits to this and other websites.

• Google's use of advertising cookies enables it and its partners to serve ads to you based on your visit to this Site and/or other sites on the Internet.
• You may opt out of personalized advertising by visiting Google Ads Settings. Alternatively, you can opt out of third-party vendor cookies for personalized advertising at aboutads.info/choices or youronlinechoices.eu (for EU visitors).
• More information about how Google uses data when you use our partners' sites or apps can be found in Google's "How Google uses information from sites or apps that use our services" page.

We do not control the cookies placed by advertising partners, and this Privacy Policy does not apply to their practices. Each advertising network has its own privacy policy; we encourage you to read them.

4. Server Log Data

Like virtually every website, our hosting provider may automatically record standard technical information when you visit the Site — such as your IP address, browser type, operating system, referring pages, and timestamps. This data is used solely for security and diagnostic purposes (for example, detecting malicious traffic) and is not used to personally identify you or build advertising profiles by us.

5. Your Rights Under the GDPR (European Union)

If you are located in the European Economic Area, you have certain rights under the General Data Protection Regulation (GDPR), including:

• The right to access, rectify, or erase personal data relating to you;
• The right to restrict or object to processing;
• The right to data portability;
• The right to lodge a complaint with your local supervisory authority.

Because we collect no personal data of our own, most of these rights concern data held by third parties (such as advertising partners). For requests concerning data we may hold (e.g., in server logs), contact us at [email protected].

6. Your Rights Under the CCPA (California)

If you are a California resident, the California Consumer Privacy Act (CCPA) grants you the right to know what personal information is collected about you and whether it is sold or shared. We do not sell or share personal information. Since we collect no personal data of our own, there is nothing to request, access, or delete — but if you believe otherwise, contact us at [email protected] and we will respond promptly.

7. Children's Privacy

The Site is not directed at children under the age of 13, and we do not knowingly collect personal information from children under 13. Since the Site does not collect personal information from anyone, no such collection from children occurs. If you believe a child has provided personal information through the Site, please contact us so we can investigate.

8. Third-Party Links

The Site contains links to third-party websites (for example, ad networks and resources linked from our articles). We are not responsible for the content or privacy practices of those websites. This Privacy Policy applies only to information handled on sudokuknacker.com.

9. Data Security

Because your puzzle data, photos, and preferences never leave your device, the main security boundary is your own browser. We recommend keeping your browser up to date and using standard precautions when sharing puzzles as screenshots, since a screenshot may contain anything visible on screen.

10. Changes to This Policy

We may update this Privacy Policy from time to time to reflect changes in the Site, our advertising setup, or applicable law. The "Last updated" date at the top of this page shows when the current version took effect. Material changes will be highlighted on this page.

11. Contact

Questions about this policy? Contact us at [email protected] or through our contact page.