In this test to compare XML vs JSON files data size, I transformed a sample of our XML data files to JSON, and I’ve obtained the following results:

File Name XML Size (bytes) JSON Size (bytes) Difference (bytes) Difference (%)
groups 6.218 3.379 - 2.839 -45.6 %
matches 14.541 8.823 -5.718 -39,3 %
scorers 1.250 652 -598 -47,8 %
TOTAL/Average 22.009 12.854 -9.155 -41,6 %

Well, after this first experiment it seems that I can save about 41,5 % on my data size if I change from XML to JSON files.

But wait! And if I reduce my tag/field names’ length to only 2 characters long?

Here are the new results that I obtained after that change…

File Name XML Size (bytes) JSON Size (bytes) Difference (bytes) Difference (%)
groups 3.444 2.934 -510 -14,8 %
matches 8.189 7.154 -1.035 -12,6 %
scorers 756 556 -200 -26,5 %
TOTAL/Average 12.389 10.644 -1.745 -14,1 %

Well, that size difference becomes reduced from near 41,5% to about 14%! It seems that with JSON I can save at least almost 2 KB per App update.

If I have 1.000 updates/day it gives less 2 MB of bandwidth which is perfectly negligible.With 1.000.000 updates/day it gives 2 GB/day, which becomes about 60 GB/month. It’s true that can save me some bucks if I’m paying a non unlimited bandwidth hosting service. But maybe it isn’t sufficient to make me change my App, specially if it doesn’t will make my App to be implemented faster and run significantly better.

By the way, until I publish the next post “JSON vs XML – Part 2: Parsing and Display Speed“, I recommend that you read an interesting article from Nicholas C. Zakas, which I found among many other articles about XML vs JSON: “Is JSON better than XML?“.

It compares several aspects of those two technologies in a succinct way.

Note: This is the first post of the “JSON vs XML – Data Size, Parsing and Display Speed” set.