Desktop application with XML-RPC calls for MacOS

We need an app that allows users to manage the setup of the domains they hired with us. The app core is XML-RPC, because the app makes requests to our API which sends responses with all data needed. Then, the app shows this information and the users are able to change it. The data are about domains: zones, subdomains and DNS. This app will allow to users make a pointer to their dinamyc IP of their PC's. The users have to login to the application. We have developed this app for Windows, and it will be useful to know the limitations. We provide all the commands to call, the test user, and screenshots about design...