Privacy and cookies

Sudoku works without sign-up. We never ask for your name, email or phone number and don't create accounts.

What is stored in your browser

• Unfinished puzzles — digits, notes, time and move history, so you can close the tab and continue later.
• Statistics — how many puzzles you have solved and your best time for each level.
• Settings — theme, highlighting, mistake checking and your language (the sd_lang cookie).

This data stays on your device (localStorage) and is not sent to the server. You can delete it by clearing site data in your browser settings.

What the server sees

Like any website, the server receives technical request data: IP address, browser and the requested page. It is used only to run the site and protect it from abuse.

Ads and analytics

If the site shows ads or uses visitor analytics, those services may set their own cookies under their own policies.