We tested this at $dayjob and JSON+gzip wins hands down because you already have an optimized native-code parser in the browser. Large-ish arrays of similar JS

We tested this at $dayjob and JSON+gzip wins hands down because you already have an optimized native-code parser in the browser. Large-ish arrays of similar JSON objects compress very well with gzip, and ultimately parse more quickly than JS-based protobuf or msgpack, at least in our testing.