In this chapter, you learned how to design a REST API and changed your Play framework application in order to have Swagger support. You created a Scala client library using proxy techniques, as well as Scala tests for the APIs. Additionally, you were introduced to back pressure using the leaky bucket algorithm.
In the next chapter, which will be the final chapter, you will learn about software architecture and scalability/resiliency techniques, such as discoverability, load balancers, caches, Akka Cluster, and the Amazon Cloud.