Website Tools

HTML Validator

Scan a live page's HTML for structural errors, missing tags and accessibility issues.

Not sure what to enter? Try an example: example.com

Free & instant No signup How to use FAQ

Enter a URL to check the page's HTML structure and get a list of errors and warnings, from unclosed tags to missing attributes.

Why validate a page's HTML?

Broken HTML - unclosed tags, duplicate IDs, missing attributes - can make pages render differently between browsers, confuse assistive technology and make it harder for search engines to read the content. This validator fetches the page and lists structural and accessibility issues it finds.

How to validate a webpage's HTML

Enter the domain or URL in the box above.
Click Validate HTML.
Start with errors, then warnings - fix missing alt text, unclosed tags and duplicate IDs first.
Re-run the check after deploying your fixes.

Related checks

To check the page's stylesheets, use the CSS Validator.
To review headings for SEO and accessibility, use the Heading Structure Checker.

Not every validation error matters - fix unclosed tags, duplicate IDs and missing attributes first, as those cause real display and accessibility problems. JustChecker monitors uptime and response time so broken releases are caught fast.

Frequently Asked Questions

Small errors rarely affect rankings because browsers and Google are forgiving. Serious ones - broken head sections, missing title or duplicated tags - can stop search engines reading key information.

Anything in the head (title, meta tags, canonical), missing alt text and lang attributes, and unclosed elements that break the layout. Cosmetic warnings can wait.

Report them to the theme or plugin author, or override the template in a child theme. Many come from older themes, which is another reason to keep them updated.

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