How do I validate my HTML against W3C standards?

CodeFrog integrates W3C HTML validation alongside accessibility, SEO, and security tests in a single scan. It catches unclosed tags, invalid attributes, improper nesting, deprecated elements, and other standards violations.

HTML errors can cause unpredictable rendering across browsers and hurt accessibility (screen readers depend on valid HTML structure). CodeFrog works on localhost, so you can fix HTML issues during development.