A method is described that involves causing a received Web service's message body to be de-serialized into an object oriented token stream with an event based reader and identifying a Web services endpoint method with a message key that was in the token stream. The method also involves obtaining, with the message key, a description of the endpoint method's input parameters from cached data that contains information pertaining to the Web service. The method also involves identifying the parameters within a second token stream generated from the received Web service's message body. The method also involves causing an object oriented response message body to be serialized with an event based writer into a Web services message that is a response to the received Web services message.