PortType

PortType is a term from the Web Services Description Language (WSDL) used to define an abstract set of operations that a web service offers. It represents a protocol-neutral interface, describing what the service can do and how messages flow between a client and the service, independent of the underlying transport or encoding.

A portType contains one or more operation elements. Each operation specifies the input, output, and, optionally, faults that may be produced during execution. The input and output reference messages, which in turn reference data types defined elsewhere (such as XML schemas). This separation allows the same portType to be bound to different protocols without changing the abstract interface.

In a typical WSDL document, a portType is bound to a concrete protocol through a binding element. The binding provides details such as the transport protocol, data encoding, and protocol-specific conventions. A service then groups one or more ports, each exposing a binding that ties a portType to a reachable endpoint. This structure enables clients to discover the service interface independently of how or where the service is hosted.

Over time, the terminology evolved. In WSDL 1.1 the concept is portType; in WSDL 2.0 the corresponding concept is often described as an interface, reflecting a shift toward a more unified description. Nevertheless, portType remains a reference in legacy documents and tools that describe WSDL 1.1 or compatibility layers.

See also: Web services, WSDL, interface, binding, operation, message.