[grncdr]

I will just steal the first paragraph from https://hexdocs.pm/phoenix/presence.html, but you can read much more about it there.

> Phoenix Presence is a feature which allows you to register process information on a topic and replicate it transparently across a cluster. It's a combination of both a server-side and client-side library, which makes it simple to implement. A simple use-case would be showing which users are currently online in an application.

[quickthrower2]

I see! Funny enough the app of the company I work for does this. The tech is simply running a stateful server behind the web server.