Protobuf also does not declare its schema. Message parsers can be generated from a schema, but that's also true for REST over JSON. Even ad hoc REST APIs often

Protobuf also does not declare its schema. Message parsers can be generated from a schema, but that's also true for REST over JSON. Even ad hoc REST APIs often have better self-declaration of resource types than protobuf. (I still like protobuf, but the schemas are a terrible reason to like it.)