How does Envoyer work?

Hi 👋,

I wanted to understand and learn how envoyer works under the hood. The reason I am looking at this is because I want to build a tool which will run various tasks on server ex. Run a script on server, monitor jobs, run jobs on server etc.

Now from what I have seen many SaaS apps do is generate an SSH key to be put on server and then connect to it. From there on I have no idea how on click of button we can run a script on server and also monitor the status/output of the command/script running on server.

Any explanation/links to resources appreciated.

Thanks, Prasad Chinwal