XML Validator

Validate XML data and check well-formedness with detailed error reporting, structure analysis, and namespace detection.

Drop an .xml file here or browse

XML Data:

Try examples:

Valid document With namespaces Unclosed tag Mismatched tags Bad attribute

How It Works

This tool validates your XML using the browser's native DOMParser, which checks for well-formedness according to the W3C XML 1.0 specification. All processing happens entirely in your browser — no data is sent to any server.

What Gets Checked

Well-formed XML structure (properly opened and closed tags)
Matching tag names (case-sensitive)
Properly quoted attribute values
Single root element requirement
Correct nesting of elements
Valid character references and entities

XML Syntax Rules

Elements must have closing tags: <tag>...</tag> or self-close: <tag />
Tag names are case-sensitive: <Name> ≠ <name>
Attribute values must be quoted: id="1" or id='1'
Documents must have exactly one root element
Special characters must be escaped: < > & " '
Comments use  syntax
CDATA sections: <![CDATA[ ... ]]>

Common Errors

Error	Example	Fix
Unclosed tag	`<item>text`	`<item>text</item>`
Mismatched tags	`<a>text</b>`	`<a>text</a>`
Unquoted attribute	`<item id=1>`	`<item id="1">`
Unescaped &	`<p>A & B</p>`	`<p>A & B</p>`
Multiple roots	`<a/><b/>`	`<root><a/><b/></root>`

Tip: Need to format or beautify your XML? Try the XML Formatter for pretty-printing, minification, and tree view.

Embed This Util

You can embed this util on your own site as a widget. Adding ?embed=1 to the URL loads a compact version with just the tool itself; no header, menu, or documentation. Paste this snippet into your HTML:

Copy snippet Adjust the height to taste.

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