If most of your communication is between two containers sitting inside a Kubernetes cluster then using GRPC is a no brainer as you get fast performance backed b

If most of your communication is between two containers sitting inside a Kubernetes cluster then using GRPC is a no brainer as you get fast performance backed by a strongly typed interface definition language. No human is going to be looking at the traffic so using a binary format makes total sense. In my experience it's also faster to develop GRPC microservices as you spend less time dealing with Serialization and Deserialization. The only main downsides are the quirks of Protobuf but they are pretty easy to get used to. Combining with GraphQL you can get a pretty high performance microservice stack, especially if you develop your microservices in Go and use a GraphQL Gateway like Apollo to stitch the whole thing together.