Welcome to the W3C Markup Validation Service; a free service that checks documents like HTML and XHTML for conformance to W3C Recommendations and other standards.
You can enter a URI in the Address field below,
and have the page validated:
If you want to upload a file from your computer and have it validated, you can use this form:
There is also an Extended Interface available if you want to set any advanced options, and a Extended File Upload Interface if you want to validate uploaded files with advanced options.
These are the most recent major changes to this service. See "What's New" for more details.