OpenEdge Web services use the request/response model for invoking the Web service and handling the results. The client sends a request message to the Web service, and the Web service returns a response message back to the same client.

Usually, client interfaces expose this request/response pair as a single object method. When the client executes the method, the underlying interface sends a SOAP request message containing any method input parameters and receives a SOAP response message containing any method output parameters and any return value.