XML Validator & Formatter
Validate, format, and analyze XML documents with comprehensive error checking
XML Input
Sample Templates:
Formatted Output
XML Validation Guide
Well-formed XML Requirements
- All tags must be properly closed
<tag>content</tag> or <tag/>
- Tags must be properly nested
<outer><inner></inner></outer>
- Attribute values must be quoted
<tag attribute="value">
- XML declaration should be first
<?xml version="1.0" encoding="UTF-8"?>
Common Validation Errors
- Unclosed tags
Missing closing tag for opened element
- Invalid characters
Special characters not properly escaped
- Duplicate attributes
Same attribute defined multiple times
- Malformed declarations
Incorrect XML or DOCTYPE declarations
Professional XML Validator & Formatter Tool
Validate, format, and analyze XML documents with our comprehensive online XML validation tool. Whether you're working with configuration files, RSS feeds, SVG graphics, or any XML-based format, our tool provides detailed syntax checking, error detection, and beautiful formatting capabilities.
Perfect for developers, system administrators, and content creators who need to ensure their XML documents are well-formed, valid, and properly structured. Get instant feedback with detailed error reports and professional formatting options.
Validation Features
- Syntax Validation
Check XML syntax and ensure documents are well-formed
- Error Detection
Detailed error reports with line and column numbers
- Structure Analysis
Analyze document structure and identify potential issues
- Real-time Validation
Instant validation as you type or paste XML content
- Warning System
Identify potential issues and best practice violations
- Document Statistics
Get detailed stats on elements, attributes, and structure
Formatting Options
Our formatter provides professional XML formatting with customizable indentation, attribute sorting, and preservation options. Export formatted XML or copy to clipboard for immediate use in your projects.
Understanding XML Validation
XML (eXtensible Markup Language) is a markup language that defines rules for encoding documents in a format that is both human-readable and machine-readable. Proper XML validation ensures that your documents follow these rules and can be processed correctly by XML parsers and applications.
Well-formed vs Valid XML
Well-formed XML follows the basic syntax rules of XML: all tags are properly closed, elements are properly nested, attribute values are quoted, and the document has a single root element. This is the minimum requirement for any XML document.
Valid XML goes beyond being well-formed and also conforms to a specific schema or DTD (Document Type Definition). Valid XML not only follows syntax rules but also adheres to the structure and data types defined in its schema.
Common XML Validation Errors
The most common XML validation errors include unclosed tags, improperly nested elements, unquoted attribute values, and invalid characters. Our validator provides detailed error messages with exact line and column numbers to help you quickly identify and fix these issues.
XML Use Cases & Applications
Configuration Files
Validate application configuration files, web.config files, and system settings to ensure proper application behavior and deployment.
RSS & XML Feeds
Validate RSS feeds, Atom feeds, and other XML-based content syndication formats to ensure compatibility with feed readers and aggregators.
SVG & Graphics
Validate SVG graphics files and other XML-based graphics formats to ensure proper rendering and compatibility across different viewers.
Advanced XML Formatting Features
Our XML formatter goes beyond basic pretty-printing to provide professional-grade formatting options that make your XML documents more readable and maintainable.
Customizable Indentation
Choose from different indentation options including 2-space, 4-space, 8-space, or no indentation. The formatter intelligently handles nested elements and maintains proper structure while applying your preferred indentation style.
Attribute Management
Optionally sort attributes alphabetically for consistent formatting across your XML documents. This feature is particularly useful for version control and collaborative development where consistent formatting reduces diff noise.
Comment and Whitespace Preservation
Control how comments and whitespace are handled during formatting. Preserve important comments while cleaning up unnecessary whitespace, or maintain exact whitespace formatting when required for specific applications.
XML Best Practices & Guidelines
1. Use Meaningful Element Names: Choose descriptive element names that clearly indicate the content they contain. Avoid abbreviations and use consistent naming conventions throughout your document.
2. Proper Nesting Structure: Ensure elements are properly nested and follow a logical hierarchy. Parent elements should contain related child elements, and the structure should reflect the data relationships.
3. Use Attributes Appropriately: Use attributes for metadata and elements for content. Attributes should contain simple values that describe or modify the element, while complex content should be in child elements.
4. Include XML Declaration: Always include an XML declaration at the beginning of your document specifying the version and encoding. This ensures proper parsing and character handling.
5. Validate Regularly: Use XML validation tools regularly during development to catch errors early and ensure your documents remain well-formed and valid throughout the development process.
Frequently Asked Questions
What makes XML well-formed?
Well-formed XML must have all tags properly closed, elements properly nested, attribute values quoted, and a single root element. It must also follow XML syntax rules for character encoding and special characters.
Can this tool validate against XML schemas?
Currently, our tool focuses on well-formedness and structural validation. Schema validation (XSD, DTD) is planned for future releases. The tool will identify structural issues and provide comprehensive syntax checking.
How does the formatting preserve my document structure?
Our formatter analyzes the XML structure and applies consistent indentation based on element nesting. Comments and content are preserved while improving readability through proper formatting and optional attribute sorting.
Is there a file size limit for XML validation?
The tool processes XML in your browser, so limits depend on your device's memory. For optimal performance, we recommend files under 5MB. Large files may experience slower processing but will still be validated accurately.
Are my XML documents stored on your servers?
No, all XML processing happens locally in your browser. Your documents are never uploaded to our servers or transmitted anywhere, ensuring complete privacy and security of your sensitive XML data and configurations.