The type system for SOAP messages — defines the shape of request and response data.
XSD defines data types used in SOAP messages:
- Simple types: string, decimal, integer, dateTime, enumerations
- Complex types: structured objects with child elements and attributes
- Restrictions: patterns, min/max values, required fields
Validate your outgoing SOAP payloads against the XSD before sending. This catches type mismatches (e.g., sending '5 lbs' when a decimal is expected) with clear error messages instead of cryptic carrier faults.