The W3C Markup Validation Service

Validate:

by URL
by File Upload
by direct Input

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.

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

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

Recent Updates

2006-02-20: Markup Validator v0.7.2 Released: Releasing version 0.7.2 of the Markup Validator, a maintenance release updating the codebase for compatibility issues with recent versions of the Config::General perl module, as well as including minor fixes in document types and character encoding support, and documentation.
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.

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.