Sudoku

Put a Free Sudoku Game on Your Website

One line of HTML gives your visitors a complete Sudoku board — four difficulty levels, pencil notes, undo, hints and a timer — running inside your page. It is free, there is nothing to sign up for, no API key to request, and no tracking script of ours touches your visitors.

The code

Paste this wherever you want the board to appear. That is the whole installation; there is no second step.

<iframe src="https://sudokugames.online/embed"
        width="100%" height="940" loading="lazy"
        style="border:0;max-width:560px"
        title="Sudoku"></iframe>

You can see exactly what your visitors will get by playing the same board on the home page — the embed runs the identical game, with the site header, footer and cookie notice stripped out.

Choosing a height

An iframe cannot measure its own contents without JavaScript running on your page, so the height has to be a fixed number rather than something the board negotiates with you. The board's height changes with the width you give it, because the layout stacks the number pad under the grid on narrow widths and puts it alongside on wider ones.

Measured heights at the widths people actually use:

  • 360px wide — the board needs about 740px of height.
  • 480px wide — about 915px, the tallest case, because this is where the layout stacks.
  • 560px wide — about 808px, with the pad moved alongside the grid.

The snippet above uses 940, which clears all three. Being too tall costs you a strip of background colour, because the embed paints its own; being too short cuts off the bottom of the board and hides the credit line. If 940 leaves a visible gap at your width, trim it — the slack shows as colour, not as an empty white band.

What it costs you

Nothing, and there is no catch to go looking for. The frame carries one small line crediting this site, which is the only thing asked in return and the reason the widget can stay free. Beyond that:

  • No analytics of ours run on your visitors. The embed route is excluded from the site's own measurement.
  • No cookies are set on your domain. An iframe cannot write to its parent, and the game's saved progress stays in the frame's own storage.
  • It loads lazily. The snippet sets loading="lazy", so the board does not download until a visitor scrolls near it and your page's own loading speed is unaffected.
  • No account, no key, no quota. There is nothing to register and nothing that can expire and break your page later.

Pasting it into the usual platforms

The snippet is plain HTML, so anywhere that accepts an embed or custom HTML block will take it. The specific spot differs by platform:

  • WordPress — add a Custom HTML block in the editor and paste it in. Do not use a Paragraph block; it will escape the tags and show you the code as text.
  • Squarespace — insert a Code block and paste. Leave the block's display setting on HTML rather than Markdown.
  • Wix — Add → Embed → Embed HTML, then choose the "Code" option rather than "Website address".
  • Blogger — switch the post editor from Compose to HTML view, then paste.
  • Notion — Notion does not accept raw HTML, so paste https://sudokugames.online/embed on its own line and choose Create embed.
  • A plain HTML site — paste it straight into the page body. There is no script tag and nothing to put in <head>.

If the board does not appear

Almost every failed embed is one of three things, in this order of likelihood:

  • The editor escaped the HTML. If you can see the <iframe> tag as text on the published page, you pasted into a rich-text field rather than an HTML one. Use the Custom HTML or Code block for your platform above.
  • Your page is served over plain HTTP. Browsers block an HTTPS frame inside an HTTP page as mixed content. The fix is on your side — serve your page over HTTPS.
  • A content security policy is blocking it. If your site sends a Content-Security-Policy header with a frame-src directive, add https://sudokugames.online to it. Nothing needs changing on this end — the embed route deliberately allows framing from anywhere.

What your visitors get

The same game as the full site, not a cut-down demo. Four difficulty levels they can switch between, pencil notes for candidates, unlimited undo, three hints per puzzle, a pause button, keyboard support, and a fresh puzzle whenever they finish one. Every puzzle has exactly one solution and can be reached by pure deduction, so nobody ever has to guess.

If you would rather send people to a full page than frame one, the level pages work just as well as a link: easy, medium, hard and expert. There are also printable sheets if your readers want something to take away from the screen, and a solver for the grid they are stuck on.

Can I change how it looks?

Within limits. The width, height and max-width in the snippet are yours to set, and the board scales down to whatever width you give it. The colours are not configurable — the embed follows the visitor's own light or dark preference the same way the main site does, which is usually what you want inside someone else's design rather than a fixed palette fighting it.

If you need something the widget cannot do, the contact page reaches a person.