With projects like Doorkeeper, OAuth has pretty solid support in Rails when dealing with one application. However, when Rails applications get larger, many project teams break up their monolithic application into services. Some suggest installing Doorkeeper on every service, whereas others recommend routing all traffic through a single service. Recently, we worked on a project where neither of these solutions seemed right. Join us as we talk about our experience in federating OAuth in order to handle over 30,000 concurrent users.