What is a WSDL?

• WSDL stands for Web Services Description Language
• WSDL is a XML document used to describe Web Services.
  

The high level structure of a WSDL looks like the below one.

WSDL

<definitions>
  <types>
    definition of the data types used by the web service
  </types>
  <message>
    definition of messages (data elements of an operation) used by   the web service
  </message>
  <portType>
    definition of a port (operations performed by the web service)
  </portType>
  <binding>
    definition of communication protocols used by the web service (ex: SOAP)
  </binding>
</definitions>


The WSDL document can also contain other elements, like extension elements, and a service element that makes it possible to group together the definitions of several web services in one single WSDL document.