.generate(options = {}) and returns a string to be used as the token.Doorkeeper::ApplicationController inherits from ActionController::Base. You may want to use your own controller to inherit from, to keep Doorkeeper controllers in the same context than the rest your app:Doorkeeper::ApplicationMetalController that is ActionController::API by default.handle_auth_errors to :raise. In this case Doorkeeper will raise Doorkeeper::Errors::TokenForbidden, Doorkeeper::Errors::TokenExpired, Doorkeeper::Errors::TokenRevoked or other exceptions that you need to care about.