Understanding XML Schema (XSD)

What is XSD?

XML Schema Definition (XSD) defines the structure and rules an XML document must follow — which elements, types, and order are allowed. It validates that XML is correct.

A Simple Schema

<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">
  <xs:element name="person">
    <xs:complexType>
      <xs:sequence>
        <xs:element name="name" type="xs:string"/>
        <xs:element name="age" type="xs:integer"/>
      </xs:sequence>
    </xs:complexType>
  </xs:element>
</xs:schema>

Valid Against the Schema

<person>
  <name>Sara</name>
  <age>25</age>
</person>

Common XSD Data Types

Type	Example
xs:string	"hello"
xs:integer	42
xs:decimal	3.14
xs:date	2026-01-01
xs:boolean	true

FAQs

XSD vs DTD?

XSD is newer, supports data types and namespaces; DTD is older and limited. More in our XML guides.

Why validate with a schema?

To guarantee data integrity before processing.