Ruby web server from std lib

server.rb

require 'webrick'
require 'json'

server = WEBrick::HTTPServer.new Port: 9000
server.mount_proc '/' do |request, response|
  response.body = 'Hello World from WEBrick'
end

server.mount_proc '/ping' do |request, response|
  response.body = JSON.generate({pong: true})
  response.content_type = 'application/json'
  response.status = 200
end

puts "Listening on http://localhost:8000"
puts "Press Ctrl+C to interrupt"

trap 'INT' do
  puts 'Bye!'
  server.shutdown
end
server.start