About XML Schema (XSD) Validator

Validate XML against basic XSD schema rules. Part of the DevTools Surf developer suite. Browse more tools in the XML collection.

Use Cases

• Enterprise developers validating SOAP web service messages
• Healthcare engineers verifying HL7/FHIR XML document compliance
• Financial systems developers checking FpML transaction formats
• Government contractors validating NIEM-conformant XML exchanges

Tips

• Validate element nesting against complexType definitions
• Check that required attributes are present on each element
• Test with a minimal XML document first to isolate schema errors

Fun Facts

• XML Schema Definition (XSD) became a W3C Recommendation in May 2001 — it replaced DTDs as the primary way to define XML document structure and data types.
• XSD 1.0 is one of the longest W3C specifications ever published, spanning three parts and over 400 pages — its complexity led to alternatives like RELAX NG by James Clark.
• Despite JSON's dominance in APIs, XML Schema remains critical in industries like healthcare (HL7 FHIR), finance (FpML), and government (NIEM) where strict typing is required.

FAQ

What XSD features are supported?

Common structural rules: element/attribute presence, types, occurrence (minOccurs/maxOccurs), simple type restrictions (pattern, enumeration, length). Complex schema compositions (substitutionGroup, xs:any) work but have edge cases.

Does it support multiple schema files?

`xs:include` and `xs:import` work when all files are pasted into the tool. Full catalog-based loading is beyond browser-side scope — use xmllint locally for that.

What does a validation error look like?

Each violation shows the XPath of the offending element, the expected type or constraint, and the actual value. Click to jump to the location in your XML.

Can I validate XML against JSON Schema?

No — JSON Schema applies to JSON. Convert XML to JSON first (XML Parser) if you want to reuse an existing JSON Schema.