Web Services: What and Why

A Web service is a software component that communicates with other applications and other components by encoding messages in XML and sending the messages over standard Internet protocols, such as the Hypertext Transfer Protocol (HTTP). Intuitively, a Web service is like a Web site without a user interface, serving applications instead of people. Instead of getting requests from browsers and returning Web pages in response, a Web service receives a request message formatted in XML from an application, performs a task, and returns an XML-formatted response message to that application. Because they use standard Internet protocols and exchange data via XML messages, Web services allow applications to communicate with each other regardless of the OS each is using, making it practical to integrate applications within a company as well as between companies via the public Internet. In the past, such integration was a time-consuming and highly customized process that only the very largest of companies could afford to undertake. With Web services, Microsoft and others hope to make it commonplace.