A Web service can be deployed using a backend component such as an Enterprise JavaBean or Java class. The operation of the Web service can be mapped to methods of the backend component. An interceptor can provide access to SOAP contents of a Web service invocation message, passing contents to and from the backend component. The interceptor writes response data received from the backend component to a Web service response message, which can be sent to the client invoking the Web service. A codec, such as a serializer or deserializer, can be used to convert data in the Web service invocation message and invocation response message between XML representations and Java objects for use with the backend component.