Take a look at Phoenix.Socket.Transport — Phoenix v1.8.8 and you should be implementing socket.io protocol on it.
Below article implements binary WebSocket as Socket Transport -
Phoenix Socket expect heartbeat every 60 seconds - I think you have to figure out something on client side.
If phoenix socket doesn’t work out - may be you have to use cowboy web socket.
I have a question - why do you want to use elixir/erlang for socket.io ?
