This is false, I've optimized horrendously large json parsing by simply rotating the data in a table form and using a binary serializer/deserializer (c.js provided by kdb: https://github.com/KxSystems/kdb/blob/master/c/c.js ).

It's insanely faster to parse binary into js object without going through json at all than parsing string json, and we transformed a dumb application from slow death to "oh wow no need to optimize further, all perf problems are now fixed" simply by switching the serialization format (faster to download, faster to deserialize, faster to access).

It even helps the backend to serialize faster than writing enormous ASCII strings just to talk to the browser memory structure. Dont forget these json format are just better xml and still made for humans. Machines can work well with structures closer to the memory layout, for instance sending the header once and subsequent objects in ordered attributes with separator is closer to how an object is stored and accessed by JS.

I suppose a mistake we all make after years of JSON is thinking it represents objects for the browser but an object is always a byte array with an offset per attribute descriptor. So send the attribute descriptors and their type (which will describe a size too) first and then just fill.