If anyone has had direct experience using XML/SOAP Based Web services, I have what possibly could be a very dumb question. In an effort to understand the technology a bit more, I have started to write my own code, and began wonder a few things. If you are using XML to transfer data over HTTP in and out of your "service" and your server only needs to receive-parse-process-respond to requests, why have all the overhead of all these large parsing libraries? If you have described the XML of your service via a WSDL, you know what to expect from the request (valid/invalid) and you have given the user of your service what the XML response will look like. So instead of using all the libraries and App servers out there, why isn't it appropriate to follow the standard and write your own?? Am I missing something??