Can you explain what the WSDL schema is and what it is used for in web services?

WSDL (Web Services Description Language) is an XML schema that describes a web service. It contains information about:

• available methods (operations) of the service;
• message formats (input and output);
• protocols and addresses where the service is accessible;
• data types used in messages.

WSDL is used to automate interaction between the client and the server: the client can generate code to call the service based on the description from WSDL, without the need to manually understand the implementation details.