Build & Deploy



Ruby applications are detected when the application contains at least one of the following:

  • A Gemfile, which indicates a Ruby application
  • A, which indicates a Rack application
  • A config/environment.rb, which indicates a Rails 2 application
  • A config/application.rb containing the string Rails::Application, which indicates a Rails 3 application


By default, your application is built using the Ruby version defined in your Gemfile.

If your Gemfile does not contain a ruby entry, your app will be built using Ruby (MRI) 3.1.2.