Web services are web-based application that translates your application into browser-based application
using XML, SOAP, WSDL and UDDI. World Wide Web Consortium (W3C) has defined it as a software system designed to communicate machine to machine over a network without time-consuming custom coding. These applications usually allow organizations to communicate data without interfering in one another’s system.

In web service, XML tags the data within the message; SOAP is a protocol specification that transfers the data, the Web Services Description Language (WSDL) defines the description of available service while Universal Description Discovery and Integration (UDDI) provides the list of available services.

Web service does not provide the Graphics User Interface by default but the programmers can add it to provide it to the clients by making it as a specific web service application.