What about non-web client/server applications though? I'm thinking online games / MMOs that require much more realtime communications than REST does. I have no idea what is used now, socket connections with something on the line I suppose.
For a game, I would maybe use Protobuf and grpc. There is serialization and deserializarion required. Something like flatbuffers or capnproto where the wireformat matches language data layout makes for extremely efficient parsing (though it may not be as network efficient). Really depends on how you structure your data.
