Built my startup on phoenix and I can vouch that it was 100% the right decision. code is easy to modify/reason about. Performance smokes rails by a wide margin and its websocket support is simply amazing. There's a few really great libraries for it that just let you scale very efficiently without much effort.

https://github.com/elixir-nx/axon -> AI/neural networks

https://elixir-broadway.org/ -> consume streams from kafka or rabbitmq

https://oban.pro/ -> job processing

https://membrane.stream/ -> webrtc (make a video confrencing app)