[imtringued]

Yeah this is something people don't seem to want to get into their heads. If all you care is minimizing transferred bytes, then gzip+JSON is actually surprisingly competitive, to the point where you probably shouldn't even bother with anything else.

Meanwhile if you care about parsing speed, there is MessagePack and CBOR.

If any form of parsing is too expensive for you, you're better off with FlatBuffers and capnproto.

Finally there is the holy grail: Use JIT compilation to generate "serialization" and "deserialization" code at runtime through schema negotiation, whenever you create a long lived connection. Since your protocol is unique for every (origin, destination) architecture+schema tuple, you can in theory write out the data in a way that the target machine can directly interpret as memory after sanity checking the pointers. This could beat JSON, MessagePack, CBOR, FlatBuffers and capnproto in a single "protocol".

And then there is protobuf/grpc, which seems to be in this weird place, where it is not particularly good at anything.