HTML Formatter/Validator

Format, minify, validate, and visualize HTML as a DOM tree.

HTML Input

Output

<!DOCTYPE html>
<html>
  <head>
    <title>
      Sample
    </title>
  </head>
  <body>
    <div class="container">
      <h1>
        Hello
      </h1>
      <p>
        Some
        <strong>
          bold
        </strong>
        text.
      </p>
      <img src="logo.png" alt="logo">
      <ul>
        <li>
          One
        </li>
        <li>
          Two
        </li>
      </ul>
    </div>
  </body>
</html>

Formatting is tag-aware: void elements, pre/textarea/script content, and comments are handled correctly. Validation uses the browser's built-in HTML5 parser.

//Share this tool

//Related tools

JSON Formatter

Format, validate, minify, and prettify JSON data instantly.

JWT Decoder

Decode and inspect JWT tokens: header, payload, signature, expiration.

Base64 Encoder/Decoder

Encode text or files to Base64 and decode back. UTF-8 safe.

Regex Tester

Test regular expressions in real-time with match highlighting and groups.

Format, minify, and validate HTML with a tag-aware formatter that respects pre and code blocks. Visualize document structure as a DOM tree and catch parse errors with the browser parser.

[x]Features

-Tag-aware formatting with 2-space indent
-Minify mode with comment stripping
-DOM tree visualization of document structure
-HTML5 parser validation with error messages
-Preserves pre, textarea, script, and style content
-Download formatted output as .html file

>Use Cases

>Cleaning up generated or copy-pasted HTML
>Reviewing email templates before sending
>Debugging malformed markup
>Learning document structure from the DOM tree view

Frequently Asked Questions

>How is HTML validated??

Validation uses the browser's built-in HTML5 parser. It reports parse errors, though browsers are lenient with invalid HTML by design.

>Does formatting preserve pre and code blocks??

Yes, the formatter is tag-aware and leaves the content of pre, textarea, script, and style elements untouched.