With Hanami you can build your project by following the Monolith-First principle. As you add more code to the project, you can grow it organically, by splitting the project into several Hanami apps.

A real world Hanami project could have dozens of Hanami apps in the same project (for example, web for the front-end, admin for the administration, api for a JSON API, etc…) You might want to deploy them to different servers, even though they’re all a part of the same project. For example, most of the servers could be used for the web app (for customers on the site), a couple could be used for an api (perhaps for customers using mobile apps), and you could have a single server running and admin application, since it’ll likely get less traffic than the other two.

We support this, with selective booting:

# config/environment.rb
# ...
Hanami.configure do
  if Hanami.app?(:web)
    require_relative '../apps/web/application'
    mount Web::Application, at: '/'
  end
  if Hanami.app?(:api)
    require_relative '../apps/api/application'
    mount Api::Application, at: '/api'
  end
  if Hanami.app?(:admin)
    require_relative '../apps/admin/application'
    mount Admin::Application, at: '/admin'
  end
end

You can declare which apps to use with the HANAMI_APPS environment variable. You can provide a single app, or several apps (joined with commas):

$ HANAMI_APPS=web,api bundle exec hanami server

This would start only the web and api applications.