Check the markup (HTML, XHTML) of Web documents

Validate by URI

Validate a document online:

More Options

Validate by File Upload

Upload a document for validation:

More Options

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

:

More Options

This validator checks the Markup Validity of Web documents in HTML, XHTML, SMIL, MathML, etc. 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.

This is the markup Validator v0.8.0-dev. Latest Stable release of the validator was version 0.7.4, released 14 Nov, 2006.