The simplest and most basic definition that I can give you is that a Web service is an application that provides a Web API.

Ann Thomas Manes

Business and IT:

This chapter is primarily for IT. However, business users might find it useful to glance at it. It is common knowledge that service oriented architectures (SOAs) can use any standard technology, not just Web services, for registry, discovery and especially exchange of

messages or invocations between service providers and con-

sumers. That is true. However, Web services remain by far the most promising standards for robust inter-and intra-enterprise exchanges. Furthermore, the standards discussed here, especially Universal Description, Discovery, and Integration (UDDI) and Web Services Description Language (WSDL), can be used to publish and describe any type of business or service, respectively. As this chapter demonstrates, UDDI is used to publish information for Yellow Pages about businesses, not just technical specifications. A browser can be used to search and access information about business and the services that are supported by each-hence the relevance of UDDI to business users. WSDL gets more technical and provides additional details about the supported services. The third standard, SOAP, is the most technical and specifies the eXtensible Markup Language (XML) message structure for service provider and con-

sumer exchanges.