Web services 是一系列相互關聯的應用函數，它們可以在Internet上被調用。Web services 是獨立的、可以自己解釋自己的組件，可以在Web上發布、定位、和調用。
Web services 的種類可以為三種：
1、共享商業信息。如：新聞、天氣預報、股票行情等。
2、商業集成。如：網上拍賣、預訂系統、信用校驗等。
3、商業流程擴展。如：合并企業的制造、批發、零售等業務流程。
Web services 的業務角色和交互
可以分為service provider, service broker, and service client
Service providers create and deploy their Web services and can publish the availability of their WSDL-described services through a service registry, such as a UDDI Business Registry. service provider主要是建立發布Web services。
Service brokers register and categorize published services and provide search services. For example, UDDI acts as a service broker for WSDL-described Web services. Service brokers 是歸類并注冊Web services，以利于查詢。
Service clients use broker services such as the UDDI Business Registry to discover a needed WSDL-described service and then bind to and call the service provider.Service clients 則是在Service brokers中查找到Web services，然后綁定到Service providers并調用之。
可以參考www.ibm.com/developerworks/webservices