HTML Formatter

Format and validate HTML code with syntax highlighting

Overview

A powerful online HTML formatter and beautifier that helps you clean, format, and validate HTML code. This tool supports HTML5, ensures proper tag nesting, and provides real-time syntax highlighting to improve code readability and maintainability.

Key Benefits

  • Instant HTML formatting with customizable indentation
  • Real-time syntax validation and error detection
  • Support for HTML5 elements and attributes
  • Proper tag nesting and structure validation
  • Copy formatted HTML with a single click
  • Cross-browser compatibility checks
  • Automatic tag closing and correction

Primary Use Cases

  • Cleaning up minified HTML code
  • Formatting HTML templates
  • Preparing code for documentation
  • Debugging layout issues
  • Code review preparation

Features

Main Features

  • Real-time HTML validation and formatting
  • Customizable indentation (2-8 spaces)
  • Tag nesting verification
  • Error highlighting with messages
  • HTML5 compatibility checks
  • Syntax highlighting
  • Dark mode support

Technical Specifications

  • Handles HTML files up to 15MB
  • Supports HTML5 elements
  • Preserves conditional comments
  • Maintains DOCTYPE declarations
  • Compatible with custom data attributes

How It Works

The HTML formatter uses a sophisticated parsing engine to process your HTML code. It first validates the structure, ensures proper nesting, and then applies formatting rules to create clean, well-structured output.

Steps

  1. Paste or upload your HTML code
  2. The tool parses and validates the HTML structure
  3. Tags are properly nested and indented
  4. Missing closing tags are identified
  5. Formatting rules are applied
  6. The beautified output is displayed with syntax highlighting

Limitations

  • Maximum file size: 15MB
  • Some HTML template syntax may be altered
  • Custom script contents are not formatted

Examples

Basic HTML Formatting

Example of formatting a simple HTML structure

Input:

<!DOCTYPE html><html><head><title>Sample Page</title></head><body><div class='container'><h1>Welcome</h1><p>This is a sample paragraph.</p></div></body></html>

Output:

<!DOCTYPE html>
<html>
  <head>
    <title>Sample Page</title>
  </head>
  <body>
    <div class="container">
      <h1>Welcome</h1>
      <p>This is a sample paragraph.</p>
    </div>
  </body>
</html>

Complex HTML with Nested Elements

Formatting HTML with deeply nested elements and attributes

Input:

<nav><ul class='menu'><li><a href='#' class='active'>Home</a></li><li><div class='dropdown'><button>Products</button><div class='content'><a href='#'>Item 1</a><a href='#'>Item 2</a></div></div></li></ul></nav>

Output:

<nav>
  <ul class="menu">
    <li>
      <a href="#" class="active">Home</a>
    </li>
    <li>
      <div class="dropdown">
        <button>Products</button>
        <div class="content">
          <a href="#">Item 1</a>
          <a href="#">Item 2</a>
        </div>
      </div>
    </li>
  </ul>
</nav>

Frequently Asked Questions

What is HTML formatting?

HTML formatting is the process of organizing HTML code with proper indentation, spacing, and line breaks to improve readability while maintaining its functionality.

Does formatting affect my page appearance?

No, formatting only changes how the HTML code looks in the editor. It doesn't affect how the page appears in browsers.

Can I format minified HTML?

Yes, you can paste minified HTML and the formatter will add proper spacing and indentation to make it readable.

Will it fix HTML errors?

The formatter identifies common HTML errors and can fix basic issues like missing closing tags, but it won't fix logical or semantic errors.

Tips & Best Practices

Best Practices

  • Use semantic HTML elements
  • Maintain consistent indentation
  • Close all tags properly
  • Use descriptive class and ID names
  • Include proper DOCTYPE declaration
  • Validate your HTML regularly

Common Pitfalls

  • Incorrectly nested elements
  • Missing required attributes
  • Invalid character encoding
  • Unclosed tags
  • Improper use of semantic elements

Technical Details

Supported Formats

  • HTML5
  • XHTML
  • HTML4
  • Custom elements
  • Template syntax

Limitations

  • Maximum file size: 15MB
  • Maximum nesting depth: 100 levels
  • Maximum line length: 1000 characters

Browser Compatibility

  • Works in all modern browsers
  • Chrome 60+
  • Firefox 60+
  • Safari 12+
  • Edge 79+

Security & Privacy

Data Handling

  • All processing is done in your browser
  • No data is sent to servers
  • No data is stored or cached
  • Files are processed in memory only

Privacy Considerations

  • No cookies used for formatting
  • No tracking or analytics in the tool
  • No data collection of any kind
  • Open source code for transparency

Resources & References

Documentation

References