Check your HTML for common issues and syntax errors. Pure client-side.
An HTML checker catches common structural problems—unclosed tags, outdated patterns, or simple syntax issues—before you ship a page.
Browser-side checks are helpful for quick feedback; official validators and framework compilers remain authoritative for production accessibility and standards compliance.
Treat it as a fast local helper, not a full conformance suite.
DevToolBox tools are designed to process data in your browser whenever possible. Read our Privacy Policy and About page for details on client-side processing and network lookups.