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.

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

2005-10-18: Markup Validator v0.7.1 Released
Released version 0.7.1 of the Markup Validator, a maintenance release introducing performance enhancements and including minor fixes in the user interface and in the "Direct Input" validation results.
2005-08-08: Markup Validator v0.7.0 Released
Released version 0.7.0, including improvements in User Interface and feedback mechanisms, support for installation on Windows platform, better support for both W3C and non-W3C document types, usage of templates for validation results, and a number of bug fixes.

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.