just started to use them for an elixir/phoenix project. multi region with distributed nodes just works. feels almost magically after all the aws work I've done the past few years.
I was under the impression that fly.io today (though they are working on it) doesn’t do anything unique to make hosting elixir/Phoenix app easier.
See this comment by the fly.io team.
But we've got full-time people working on Elixir now, too; we'll see where that goes. We've still got Elixir limerence here. :)