Web Services Description Language (WSDL) is an XML-based language that provides a standardized way to describe the functionalities and operations of a web service. It defines the structure of the web service, including the input and output message formats, the operations that can be performed, and the protocols and data types used.

Key aspects and components of WSDL include:

Service Interface: WSDL defines the interface of the web service, including the operations that can be invoked and the messages exchanged.

Message Types: WSDL describes the structure of input and output messages, specifying the data types and formats.

Binding Information: WSDL defines the protocol and transport details for invoking the web service, such as HTTP, SOAP, or others.

Port Type: WSDL specifies the port type, which defines the operations supported by the web service and their input and output message types.

WSDL plays a crucial role in web service development, allowing for a clear and standardized description of the service's functionalities, enabling seamless integration and interoperability across various platforms and applications.