Action Policy is designed to be independent of any framework and does not have specific dependencies on Ruby on Rails.

You can write your policies for non-Rails applications the same way as you would do for Rails applications.

In order to have authorize! / allowed_to? / authorized methods, you will have to include ActionPolicy::Behaviour into your class (where you want to perform authorization):

class PostUpdateAction
  include ActionPolicy::Behaviour

  # provide authorization subject (performer)
  authorize :user

  attr_reader :user

  def initialize(user)
    @user = user
  end

  def call(post, params)
    authorize! post, to: :update?

    post.update!(params)
  end
end