XML Validator
Validates an XML string or file against the specified XSD schema. Well-formedness is checked first, then the document structure.
XML validation explained
Well-formed versus valid
An XML document is well-formed when it respects the syntax of XML itself: a single root element, every start tag has a matching end tag, elements are properly nested, attribute values are quoted, special characters are escaped, and names are legal.
A document is valid when, in addition to being well-formed, it conforms to a schema that describes which elements and attributes are allowed. This tool validates against XSD (XML Schema Definition).
What is an XSD?
An XML Schema is itself an XML document, written in the http://www.w3.org/2001/XMLSchema namespace. It declares elements, attributes, simple types, complex types, and a target namespace.
How the schema is located
You can paste (or upload) the XSD in the second box, or let the document point to it via xsi:noNamespaceSchemaLocation or xsi:schemaLocation attributes.
Reading the results
| Level | Meaning |
|---|---|
| error | The document violates the schema, or is not well-formed (fatal). |
| warning | Something suspicious that does not make the document invalid. |