Ruby Default Web Server | Heroku Dev CenterWhen you deploy a Ruby application without a Procfile, a default webserver will be used. For Rack this means $ bundle exec rackup is run for Rails $ rails server. Depending on the version of these libraries and what gems you have in your Gemfile, the WEBrick server may be used to run your production application. Even if your application does not use WEBrick, it is HIGHLY recommended you do not rel
