I'm not sure if the benchmarks above reflect this, but MessagePack allows you to use integers (or any data type) for map keys. This makes it a lot smaller than

I'm not sure if the benchmarks above reflect this, but MessagePack allows you to use integers (or any data type) for map keys. This makes it a lot smaller than using plaintext keys, and makes it comparable to formats like Protobuf despite the lack of formal schema. (You also lose a lot of the context-free readability of messages, so it's a tradeoff.)