Validate XML

Check XML well-formedness, matching tags, entities, and document structure.

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ToolXML Validator
Input
Output
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How it works

The parser checks matching tags, quoted attributes, entity syntax, declarations, and root structure, then returns its line and column for failures. It checks well-formedness only and does not load a DTD or XSD.

  • Well-formedness is the portable baseline.
  • Avoiding external schemas keeps the browser check deterministic.

Worked example

Valid book catalog XML
Validate a well-formed XML document with attributes
Input
											<?xml version="1.0" encoding="UTF-8"?>
<catalog>
  <book id="1">
    <title>Clean Code</title>
    <author>Robert C. Martin</author>
    <year>2008</year>
  </book>
  <book id="2">
    <title>The Pragmatic Programmer</title>
    <author>David Thomas</author>
    <year>1999</year>
  </book>
</catalog>
Output
												Valid: yes

When to use this

CI packaging, SOAP fixtures, and SVG or RSS authoring validate XML.

Edge cases

  • An unescaped ampersand fails unless it starts an entity.
  • Two root elements are not well formed.
  • Valid XML can still violate an application XSD because no schema is loaded.

References