Comment by Scarbutt

For single a web api server Elixir is going to be far behind, performance wise, against nodejs, the JVM and Go. Their big feature is reliability/clustering but in the context of web requests, scaling them is real easy today, just use a load balancer. For me Erlang/Elixir have very specific niche use cases(at which it excels at) but its fans confuse beginners promoting it as a "general purpose language" that they should use it for everything.