Gemfile source "https://rubygems.org" ruby "2.2.3" gem 'sinatra' gem 'thin' Procfile web: bundle exec rackup config.ru -p $PORT config.ru require './application' # set :root, settings.root # set :views, settings.root + '/views' run Sinatra::Application application.rb require 'sinatra' #set :root, File.dirname(__FILE__) get '/' do erb :index end views are in the folder /views/index.erb <!DOCTYPE html> <html lang="en"> <head> <!-- These meta tags come first. --> <meta charset="utf-8"> <meta http-equiv="X-UA-Compatible" content="IE=edge"> <meta name="viewport" content="width=device-width, initial-scale=1"> <title>Bootstrap Theme Example</title> </head> <body> <h1>Hello, world!</h1> <!-- Include jQuery (required) and the JS --> <script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.4/jquery.min.js"></script> </body> </html>