Privacy policy

Sudoku Online does not ask you for an account, a name or an email address to play. Your game settings, saved board and statistics stay in your own browser. The site counts anonymous game events in aggregate, with no cookies and no identifiers.

Google Analytics and Google AdSense can load only according to your consent choices where the law requires consent, and they respect Global Privacy Control. This page explains each of these in detail. It was last updated on 29 October 2026.

Who is responsible for your data?

The site is operated by Sudoku Online Editorial Team, who decides how the information described here is used. You can contact us at [email protected].

What stays in your browser?

The game saves some information in your browser’s local storage on your own device so that it can work between visits. It includes your settings, such as theme, large digits and mistake feedback; your current board, so that a paused game can resume; your statistics, such as games played and best times; your daily-puzzle streak; and your consent choice, stored under the name so:consent. This information is not sent to us. It stays on your device until you clear the site’s data in your browser. If your browser blocks storage, the game keeps it in memory only until you close the page.

What does the site count about its own use?

To see which boards and techniques are used, the site counts a short list of game events in aggregate. Examples are a game starting or finishing, a hint being used and which technique it named, notes being toggled, and a setting being changed. For a finished game it counts the level, the time taken, the hints used and the mistakes made. Only totals per day are stored. The events carry no cookie and no identifier, and the count does not record who played. If your browser sends Global Privacy Control or Do Not Track, the site does not count your events at all. To limit abuse, the server briefly uses a salted, one-way hash of your network address to cap how many events one client can send per minute. That hash is not stored with the counts.

What do Google services do?

Google Analytics

The site uses Google Analytics 4 to measure how the site is used. Where the law requires your consent, which includes the European Economic Area, the United Kingdom and Switzerland, and where we cannot tell your location, Google Analytics does not load until you agree. Elsewhere it loads unless you decline or your browser sends Global Privacy Control. When it loads, Google may set cookies and process information such as your approximate location, device and the pages you view. We use the reports in aggregate and do not try to identify individual visitors.

Advertising

The site is intended to show display advertising through Google AdSense. Advertising scripts load only when advertising is switched on and your choices allow it. In the European Economic Area, the United Kingdom and Switzerland, a Google-certified consent message must also be shown and accepted first. When ads load, Google and its partners may use cookies and similar technologies to serve and measure ads, and, if you allow it, to personalize them. Google explains how it uses information from sites that use its services in its own privacy materials.

What do servers and providers see?

Like any website, our hosting and content-delivery providers receive technical details with each request, such as your network address, the page requested and your browser type. They use this to deliver the site, keep it secure and diagnose problems. We do not use these details to build profiles of visitors. Staff accounts exist only for people who run the site, and those accounts are protected by sign-in and two-step verification. They are not available to visitors.

What choices do you have?

Change your consent at any time with the Privacy choices control in the footer, where it is shown.
Send Global Privacy Control from your browser or an extension, and the site treats analytics and advertising as declined.
Clear your data by deleting the site’s data in your browser settings. This removes your settings, saved board, statistics, streak and consent choice.
Use browser or device controls to limit cookies and advertising identifiers.

The cookie policy lists what is stored and by whom.

What are your rights?

Depending on where you live, you may have the right to ask what personal information a business holds about you, to correct or delete it, to object to certain uses and to complain to your data protection authority. The site holds no account or profile about you, so most of what exists is on your own device or with Google, and we can point you to the right place. Write to [email protected] with any request.

Is the site for children?

The site is for a general audience. It does not ask for personal information and does not knowingly collect it from children. Advertising settings for children are a matter for the person who sets up the device, and the browser controls above apply.

Where is information processed?

Google and our hosting providers may process information in countries other than your own. Where the law requires safeguards for such transfers, those providers describe them in their own terms.

How will changes be handled?

If this policy changes, the date at the top changes with it. Material changes that need your consent will be asked for again through the consent control.