How to use HTML Validator
- Drop your HTML into the field at the top of HTML Validator.
- HTML Validator updates the output automatically as you type.
- Use Copy to keep or reuse the result.
About this tool
Everything HTML Validator does happens on your own device. HTML Validator handles your HTML on your device and shows the result right away.
Generated previews are escaped or sandboxed so pasted markup cannot affect the tool. It behaves the same on desktop and mobile, with nothing stored remotely.
Frequently asked questions
What is HTML Validator for?
HTML Validator lets you validate your input right in the browser, with the result shown instantly and nothing uploaded.
Does HTML Validator cost anything?
No — HTML Validator is completely free, with no sign-up and no hidden limits.
Does HTML Validator upload my data?
No — HTML Validator processes everything locally in your browser, so nothing you enter is uploaded or stored.
Will HTML Validator change my HTML structure?
HTML Validator only reformats or analyzes what you paste; the underlying structure of your HTML is preserved.
Does HTML Validator work on mobile?
Yes — HTML Validator is just a web page and runs on any modern browser, including phones and tablets.