mod SimpleApp entry :project deps: {:cowboy, "~> 2.6"} {:plug, "~> 1.8"} {:plug_cowboy, "~> 2.0"} :app [extra_applications: [:logger]] import Plug.Conn fn init default_options IO.puts "initializing plug" default_options fn call conn:Plug.Conn.t() _options = [] IO.puts "calling plug" conn |> put_resp_content_type "text/plain" |> send_resp 200 "Hello world" # in lytx run `Plug.Adapters.Cowboy.http SimpleApp []`