I see more and more software organizations using gRPC in their service-oriented architectures, but people are also still using REST. In what use cases does it make sense to use gRPC, and when does it make sense to use REST for inter-service communication?
Interestingly, I've come across open source projects that use both REST and gRPC. For instance, Kubernetes and Docker Swarm all employ gRPC to some extent for cluster coordination, but also expose REST APIs for interfacing with master/leader nodes. Why not use gRPC up and down?