On this device
Local browser storage may contain the selected puzzle ID, entered digits, notes, undo history, elapsed time, attempt status, and game preferences. It does not create a GridHearth account or sync progress between devices.
Privacy
Your puzzle progress stays in this browser
Sudoku progress stays in your browser so you can return to a puzzle. You do not need an account. Limited website analytics help us understand site use and performance.
Your controls
Restart clears the current attempt for that puzzle. Your browser settings can remove all site storage. Private browsing and browser cleanup tools may remove it automatically.
Website analytics
The analytics reports we use may include pages viewed, referring sites, approximate country, device type, browser, operating system, navigation type, and website performance measurements. We use these reports to understand which pages are useful and to improve website performance.
Website analytics does not provide us with your name, contact details, age, gender, puzzle entries, notes, or purchase information. It is separate from the puzzle progress stored on your device.
Analytics retention
We do not export analytics to build individual visitor profiles. Our analytics reports cover at most the previous six months.
Privacy questions and requests
For questions about this notice or requests about information you have sent us, email support@gridhearth.com.
When you email us, we receive your email address and the information in your message so we can review and respond to it.
Last updated: September 25, 2026.