A Web service is a self-contained, modular application that can be accessed through a network connection. Using a Web service, the end user trades performance for increased interoperability enforced by adherence to the Simple Object Access Protocol (SOAP), Web Services Description Language (WSDL), and Extensible Markup Language (XML) open standards.
Regardless of the programming language in which it has been implemented, a Web service can be accessed from many different platforms and operating systems, thus greatly enhancing the ability for diverse applications to share data. By using many discrete Web services, each handling a limited set of specific tasks, business enterprises can dynamically and incrementally integrate by exposing their existing software in a secure and controlled environment. By providing a standardized means to invoke remote applications, Web services reduce the amount of code required for infrastructure. By enabling users to extract implementation from exposed interfaces (WSDL), Web services provide the tools needed to build a service-oriented architecture (SOA).
