Markup Validation
Developer Tools
Markup Validation
This validator checks the markup validity of Web documents in HTML, XHTML, SMIL, MathML, etc. Identify syntax errors and ensure strict standard compliance using the official W3C Validator Web Service.
Private & Secure
W3C Standard
Quick Tip
Use the URI method for public websites, File Upload for local templates, and Direct Input to quickly validate small snippets of HTML code!