Never really understood the folks pushing for RPC-over-HTTP. RPC is for systems that are close together (ie intra-DC). These simple rules work well: 1. JSON-over-HTTP for over the web 2. RPC (pick your flavor) for internal service-to-service

I will say that Amazon's flavor (Coral-RPC) works well and doesn't come with a ton of headache, its mostly "add ${ServiceName}Client to build" and incorporate into the code. Never mind its really odd config files

Related note, I've never understood why Avro didn't take off over GRPC, I've used Avro for one project and it seems much easier to use (no weird id/enumerations required for fields) while maintaining all the code-gen/byte-shaving