If you only want faster than JSON then a 'binary json's like MessagePack or JSONB (is that the PostgreSQL one?) avoids dealing with schema. If you want schema it's not like JSON.
MsgPack is great. However I’ve been curious about Amazon’s Ion. Mainly since the namespace stuff allow you to define tags upfront into ints. MagPack transfers field names as strings still unless you crest your own string to int conversion.
