Validate HTML structure, find syntax errors, unclosed tags, and invalid attributes instantly. HTML Validator is a free online tool from the ToolsRift HTML Tools collection. It runs entirely in your browser — nothing to install, no signup, and your data never leaves your device.
The validator checks for unclosed tags, mismatched tags, invalid nesting, missing required attributes, duplicate IDs, and common syntax errors.
Yes, the validator supports HTML5 elements and attributes. It checks against modern HTML standards while flagging deprecated elements.
Yes, you can validate fragments like a single div or component. The validator will note missing document structure but check the fragment syntax.