Amazon Ion – A richly-typed, self-describing, hierarchical serialization format

This reminded me of a tight-packed binary format we used in the trading systems domain almost 20 years ago. Instead of including metadata/field names in each message, it had a central message dictionary that every client/server would first download a copy from. Messages had only type IDs, followed by binary packed data in the correct field order. Because of microsecond latency requirements, we even avoided the serialization/deserialization process by making the memory format of the message and the wire format…

After working (internally) with Ion and related tooling, I'd say that I was opposite of fan. Protobuf strength is in good tooling/codegen around it (especially inside of Google), and with Ion you just have "superset of json". Ion never had nice code wrappers around serialized structures, and most of the time, especially with rich structures it was frustrating experience.