XML Formatter

Format and validate XML documents with syntax highlighting

Overview

A comprehensive online XML formatter and validator that helps you format, validate, and beautify XML documents. This tool supports various XML standards, DTD validation, and provides detailed error reporting with syntax highlighting for maximum readability.

Key Benefits

  • Instant XML formatting with customizable indentation
  • XML validation against schemas and DTDs
  • Detailed error reporting and suggestions
  • Preservation of CDATA sections and comments
  • Support for complex XML structures
  • Cross-platform compatibility
  • Namespace handling and validation

Primary Use Cases

  • Formatting XML configuration files
  • Validating XML documents
  • Preparing API responses
  • Documentation preparation
  • XML data exchange formatting

Features

Main Features

  • Real-time XML validation and formatting
  • Customizable indentation options
  • Error highlighting with line numbers
  • CDATA and comment preservation
  • Namespace support and validation
  • Copy to clipboard functionality
  • File upload and download support

Technical Specifications

  • Handles XML files up to 20MB
  • Supports XML 1.0 and 1.1
  • Preserves document structure
  • Maintains attribute ordering
  • DTD and XSD validation

How It Works

The XML formatter uses a robust parsing and formatting engine to process XML documents. It validates the structure, handles namespaces, and applies consistent formatting while preserving the document's semantic meaning.

Steps

  1. Paste or upload your XML document
  2. Document is parsed and validated
  3. Formatting rules are applied
  4. Namespaces are validated and preserved
  5. Output is generated with proper indentation
  6. Error checking and reporting is performed

Limitations

  • Maximum file size: 20MB
  • External DTD references not followed
  • Some XML extensions may not be supported

Examples

Basic XML Formatting

Simple example of formatting an XML document

Input:

<?xml version="1.0"?><root><person><name>John Doe</name><age>30</age><address><street>123 Main St</street><city>Boston</city></address></person></root>

Output:

<?xml version="1.0"?>
<root>
  <person>
    <name>John Doe</name>
    <age>30</age>
    <address>
      <street>123 Main St</street>
      <city>Boston</city>
    </address>
  </person>
</root>

XML with Namespaces

Formatting XML with namespace declarations

Input:

<?xml version="1.0"?><root xmlns:h="http://www.w3.org/TR/html4/" xmlns:f="http://www.w3schools.com/furniture"><h:table><h:tr><h:td>Apples</h:td><h:td>Bananas</h:td></h:tr></h:table><f:table><f:name>Coffee Table</f:name><f:width>80</f:width><f:length>120</f:length></f:table></root>

Output:

<?xml version="1.0"?>
<root xmlns:h="http://www.w3.org/TR/html4/"
      xmlns:f="http://www.w3schools.com/furniture">
  <h:table>
    <h:tr>
      <h:td>Apples</h:td>
      <h:td>Bananas</h:td>
    </h:tr>
  </h:table>
  <f:table>
    <f:name>Coffee Table</f:name>
    <f:width>80</f:width>
    <f:length>120</f:length>
  </f:table>
</root>

Frequently Asked Questions

What is XML formatting?

XML formatting is the process of adding proper indentation and line breaks to XML documents to make them more readable while maintaining their validity and structure.

Does formatting change my XML data?

No, formatting only changes the presentation of your XML document. The data structure and content remain exactly the same.

Can I validate XML against a schema?

Yes, you can validate XML against DTD and XSD schemas to ensure it follows the required structure and rules.

How are namespaces handled?

The formatter preserves all namespace declarations and ensures proper namespace usage throughout the document.

Tips & Best Practices

Best Practices

  • Use descriptive element names
  • Maintain consistent naming conventions
  • Properly declare namespaces
  • Include appropriate documentation
  • Validate against schemas when possible

Common Pitfalls

  • Invalid character encoding
  • Improper namespace usage
  • Unclosed XML elements
  • Missing root element
  • Incorrect attribute syntax

Technical Details

Supported Formats

  • XML 1.0 and 1.1
  • DTD validation
  • XSD schema validation
  • CDATA sections
  • Processing Instructions

Limitations

  • Maximum file size: 20MB
  • Maximum nesting depth: 1000 levels
  • Maximum element name length: 1000 characters

Browser Compatibility

  • All modern browsers supported
  • Chrome 60+
  • Firefox 60+
  • Safari 12+
  • Edge 79+

Security & Privacy

Data Handling

  • All processing is done locally
  • No server communication
  • No data storage
  • Memory-only processing

Privacy Considerations

  • No cookies used
  • No tracking
  • No data collection
  • Open source code

Resources & References

Documentation

References