HTML accessibility checker (WCAG 2.2)

Paste an HTML snippet or a whole page. The checker draws it in a sandboxed frame, runs the open-source engine axe-core against it in your browser, and lists the problems grouped by impact, each with the failing HTML, the WCAG success criterion and how to fix it. Nothing is sent to our server.

What you see in the result

• Problems grouped by impact: critical, serious, moderate and minor, the most frequent rule first.
• The success criterion of every problem as a link, for example 1.1.1 Non-text Content, with the level (A or AA).
• The failing elements: the CSS selector and the HTML of each one, so you can find it in your code.
• How to fix it, taken from our rule library, in the language of this page, with a link to the full explanation.
• "Needs a human look": cases where the rule could not decide, for example a colour on a background image. Check these by hand.

What stays on your computer

Your HTML is parsed by your browser and shown in an iframe with sandbox="allow-same-origin" and a strict content security policy: no script of your snippet runs, forms cannot be sent and links open in a new tab. By default the preview loads no images or styles from other sites; tick the option if your snippet needs an external stylesheet. axe-core is loaded from our own server the first time you press the button, and the check runs in your browser. We do not receive your code.

Snippet or whole page

A snippet is not a page, so the rules about a whole page (page title, lang attribute, landmarks, a level-one heading, skip link) are switched off for snippets. Paste a full document that starts with <!doctype html> or <html> and they are checked as well. The option "include best-practice rules" adds advice that WCAG does not require; untick it to see only WCAG problems.

What a check of pasted HTML cannot find

• Anything the page adds later. The source of a page does not contain what scripts build afterwards. Copy the rendered HTML from the developer tools ("Copy outerHTML") or test the live address with the WCAG checker.
• Styles you did not paste. Colour contrast, focus outlines and text spacing depend on CSS. Test colours with the contrast checker.
• Everything that needs a person. Whether alt text describes the image, whether the reading order makes sense, whether a keyboard user can complete the checkout, how a screen reader sounds. See how to test WCAG.

This is an automatic check, not a full audit, and it is not legal advice. A result without findings does not mean the HTML is accessible.

It is not a validator in the W3C sense

A "validator" of HTML syntax checks whether the markup follows the HTML specification. This tool checks accessibility rules: missing names on buttons, images without alternative text, form fields without labels, wrong ARIA attributes. The two are different; a page can be valid HTML and still fail WCAG, and the reverse. WCAG 2.2 no longer has the criterion 4.1.1 Parsing; broken markup matters when it breaks names, roles or relationships (4.1.2, 1.3.1).

Where it fits

Use it while you write a component or review a template from a client. For a live page use the WCAG checker, for pages behind a login the browser extension. To compare other tools see accessibility testing tools. Pandus runs this kind of check on every page of your site every week and explains each problem in the owner's language.

Frequently asked questions

Is my code sent to a server?

No. The HTML is shown and checked in your browser. Only the page itself and the checker script are loaded from our server; the code you paste is not sent anywhere.

Does it run the scripts in my HTML?

No. The preview uses a sandboxed frame without permission to run scripts, so inline scripts, event handlers and script tags do nothing. Content that scripts would add is therefore not checked.

Which rules does it use?

The axe-core rules for WCAG 2.0, 2.1 and 2.2 at levels A and AA, plus the best-practice rules if you leave that option on. The findings are explained with our own rule cards.

Is this a W3C validator?

No. It does not validate HTML syntax. It checks accessibility rules, which is a different question.

Can it confirm that my HTML meets WCAG or the EAA?

No. Automatic rules find only a part of the problems. A manual check with a keyboard and a screen reader is still needed, and this tool is not legal advice.