Cookie policy
This site sets cookies for one purpose: Google Analytics. The game itself needs none, and nothing here follows you to other websites.
What cookies are
Cookies are small pieces of data a website asks your browser to store and send back on every visit. Sites use them for logins, preferences and, on much of the web, tracking. There is nothing to log into here, and your game and settings use a different mechanism entirely, described below.
Analytics cookies
When you accept analytics, Google Analytics sets two cookies. _ga holds a randomly generated number that lets us count a returning visitor as one person rather than two, and it expires after two years. _ga_<id> keeps track of the current visit and expires the same way. Neither carries your name or anything you type.
To opt out, install Google's browser opt-out add-on, turn on your browser's tracking protection, or block cookies for this site in your browser settings. Every puzzle and feature keeps working without them.
What the game uses instead
Your saved games, settings and statistics are kept in localStorage, a browser feature that stores data on your device for a single site. Unlike cookies, localStorage is never transmitted with your requests. Nothing in it reaches us or anyone else, and it cannot follow you across the web.
For the curious, the site writes these keys and nothing more:
sudoku:settings: your preferences (theme, input mode and the rest).sudoku:save:easythroughsudoku:save:master: one saved game per difficulty, including board, notes, time and undo history.sudoku:stats: games completed and best times.
Managing it
Clearing this site's data in your browser settings removes every saved game and preference. The site keeps working; you start fresh. Most browsers expose this under privacy or site settings, per site, so you can clear this site without touching anything else.
If this changes
Adding advertising in the future would introduce further cookies from third parties. If that happens, this page and the privacy policy will describe them before they appear, and where the law requires consent you will be asked first.
Last updated: August 2026.