This is the W3C Markup Validation Service, a free service that checks Web documents in formats like HTML and XHTML for conformance to W3C Recommendations and other standards.

if you wish to validate specific content such as RSS/Atom feeds or CSS stylesheets or to find broken links, there are other validators and tools available.

Try out the future: Test the Beta version of the new validator now!

Validate Your Markup

Validate by URL

Enter the URL of the page you want to check. Advanced options are available from the Extended Interface.


Validate by File Upload

Select the file you want to upload and check. Advanced options are available from the Extended File Upload Interface.

Note: file upload may not work with Internet Explorer on some versions of Windows XP Service Pack 2, see our information page on the W3C QA Website.


Validate by Direct Input

Input the markup you would like to validate in the text area below:


Only complete documents (along with a Doctype declaration) will be validated. Advanced options are available from the Extended Direct Input Interface.

Recent Updates

2006-11-14: Markup Validator v0.7.4 Released
Maintenance release of the Markup Validator, including bug fixes to the API, documentation updates and the return of the outline feature.
2006-10-23: Markup Validator v0.7.3 Released
Maintenance release of the Markup Validator, including fixes, updates, and adding an experimental API to interface the validator with other programs and services.

These are the most recent major changes to this service. See "What's New" for more details. News for this service are also available as an ATOM feed.

Valid XHTML 1.0! Feedback: The W3C Validator Team

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