No, but anecdotally the others are probably a lot faster. And you can do even better than that with zero-copy serializations. But protobuf has very wide suppor

No, but anecdotally the others are probably a lot faster. And you can do even better than that with zero-copy serializations. But protobuf has very wide support and is decent enough in js, at least server-to-server. Having a schema is very valuable, and there are substantial size wins over JSON, even with gzip.