There is Server A, Server B and Server C. Also there are account SUPERUSER and customer accounts.
Server A is the API service, it contains all the customer credentials.
Server B is the oAuth server.
Server C is the application which is going to use the API service authenticating any customer account but first doing an internal authentication of SUPERUSER account via Server B.
In short words, I don't know if this method is appropriate, but this is what I think: My API service needs a method called "/authenticate/" only for customers authentication and receiving parameters as user and password. The thing is, what status code should I return in case of success or fail?