The W3C Markup Validation Service

Validate by URI
Validate by File Upload
Validate by Direct Input

Validate by URI

Validate a document online:

Address:

More Options

Character Encoding		Only if missing
Document Type		Only if missing
List Messages Sequentially Group Error Messages by Type
Show Source	Clean up Markup with HTML-Tidy
Show Outline	Validate error pages	Verbose Output

Validate by File Upload

Upload a document for validation:

File:

More Options

Character Encoding		Only if missing
Document Type		Only if missing
List Messages Sequentially Group Error Messages by Type
Show Source	Clean up Markup with HTML-Tidy
Show Outline	Validate error pages	Verbose Output

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

Enter the Markup (Full Document) to validate:

More Options

Validate Full Document
Use Doctype:		Only if Doctype is missing
Validate HTML fragment
Use Doctype:	HTML 4.01 XHTML 1.0
List Messages Sequentially Group Error Messages by Type
Show Source	Clean up Markup with HTML-Tidy
Show Outline	Validate error pages	Verbose Output

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, MobileOK content, or to find broken links, there are other validators and tools available.

Important This instance of the validator is either a development version used for testing purposes, or a local copy of the W3C Markup Validator software used for development and testing purposes.
The official validation service supported by the W3C is at validator.w3.org.