I'm not 100% sure yet, but I'm 100% excited about this. Problems today is that Google/Yahoo/MS have all given the government backdoor access to your email if you have those providers. This application solves that by having you host your own email service. Deploying postfix + dovecot with multi domain usage and multi alias capabilities is hard! They did all that work for you. I'm not sure how the client works yet or if you're supposed to make your own front end to this using the API from Posty. Either way I'm excited to try it out in hopes to move my email out of the hands of big companies and into my own hands.