Is it worth the effort to try to reduce JSON size?

Question

I am submitting relatively lots of data from a mobile application (up to 1000 JSON objects), that I would normally encode like this:

[{     id: 12,     score: 34,     interval: 5678,     sub: 9012 }, {     id: ... }, ...] 

I could make the payload smaller by submitting an array of arrays instead:

[[12, 34, 5678, 9012], [...], ...] 

to save some space on the property names, and recreate the objects on the server (as the schema is fixed, or at least it is a contract between the server and the client).

The payload in then submitted in a POST request, most likely over a 3G connection (or could be wifi).

It looks like I am saving some bandwidth by using nested arrays, but I'm not sure it is noticeable when gzip is applied, and I'm not sure how to precisely and objectively measure the difference.

On the other hand, the nested arrays don't feel like a good idea: they are less readable and thus harder to spot errors while debugging. Also, since we're flushing readability down the toilet, we could just flatten the array, since each child array has a fixed number of elements, the server could just slice it up and reconstruct the objects again.

Any further reading material on this topic is much appreciated.

Answer 1

JSONH, aka hpack, https://github.com/WebReflection/JSONH does something very similar to your example:

[{     id: 12,     score: 34,     interval: 5678,     sub: 9012 }, {     id: 98,     score: 76,     interval: 5432,     sub: 1098 }, ...] 

Would turn into:

[["id","score","interval","sub"],12,34,5678,9012,98,76,5432,1098,...] 

Answer 2

JSON is meant for readability. You could have an intermediate format if you're concerned about space. Create a serialize/deserialize function which takes a JSON file and creates a compressed binary storing your data as compactly as is reasonable, then read that format on the other end of the line.

See: http://en.wikipedia.org/wiki/Json First sentence: "JSON...is a lightweight text-based open standard designed for human-readable data interchange."

Essentially, my point is that humans would always see the JSON, and machines would primarily see the binary. You get the best of both worlds: readability and small data transfer (at the cost of a tiny amount of computation).