Free Online XML Validator
Validate XML syntax with detailed error messages and line numbers. Format XML with proper indentation.
code Input XML
Characters: 0
Lines: 0
Elements: -
code Output Result
Click Validate to check XML syntax, or Format to beautify XML.
Key Features
Instant Validation
Validate XML syntax using the browser's built-in DOMParser with detailed error messages.
Error Details
Get exact line and column numbers with context lines and a caret (^) marker for quick debugging.
XML Formatting
Beautify XML with proper indentation using a robust tokenizer-based formatter.
Privacy Protected
All processing happens locally in your browser. No data ever leaves your device.
Frequently Asked Questions
Getting Started
What is an XML validator?
The XML Validator checks whether an XML document is well-formed -- meaning it follows the core syntax rules of XML: a single root element, properly closed and nested tags, quoted attributes, and correctly escaped special characters. It uses the browser's built-in DOMParser to parse your XML and reports any failure with the exact line and column number.
Is this XML validator free?
Yes. All tools are completely free and run locally in your browser. No signup, no limits, no hidden costs.
Does the tool store my data?
No. Your XML data never leaves your browser. All processing happens locally on your device, ensuring complete privacy and security.
Features & Usage
Does this validator check against a DTD or XSD schema?
No, this tool validates well-formedness only -- the syntax level. Schema validation (DTD, XSD, RelaxNG) checks whether the document structure matches a predefined contract. Use this tool for the first pass to ensure the XML is parseable.
Why does my XML fail with "junk after document element"?
This error means the parser found content after the closing tag of the root element. XML allows exactly one root element, and nothing may appear after it except comments and processing instructions.
Can I validate XML with HTML entities like ?
XML only pre-defines five entities. HTML-specific entities like are not recognized in XML unless you declare them in an inline DTD.
Does the DOMParser handle XML declarations?
Yes, the browser's DOMParser correctly handles the XML declaration and processing instructions as long as your document starts with them or they appear at the top level. Always put the XML declaration on line 1, column 1.