A handler, or request handler, is a program that receives a client request for access to the service, and translates the request into a form that the service can understand. After the service has completed its task, the request handler translates the output back into a form that the client can understand, then passes the output to the client, via the communications process.
Request handlers are provided for the SOAP protocol and for the Micro Focus binary protocol. You can customize the request provided for the SOAP protocol using user exits.