Example api with plain RoR

main_controller.rb

class MainController < ApplicationController
  def songs_random
    row = ActiveRecord::Base.connection
      .execute("SELECT * FROM songs ORDER BY RANDOM() LIMIT 1;")[0]

    render json: { song: row.delete_if { |key, _| key.to_s =~ /^[0-9]+$/ } }
  end

  def words_random
    render json: { word: `shuf /usr/share/dict/words | head -1`.chomp }
  end
end

routes.rb

Ror::Application.routes.draw do
  get 'songs/random' => 'main#songs_random'
  get 'words/random' => 'main#words_random'
end