Android JSON Parsers Comparison

2 min readMar 5, 2017

There are bunch of json parsers. Recently I discovered ason. Also I heard about moshi but not used it. So I wanted to compare them.

List of parsers to compare: gson 2.8.0, jackson 2.0.1, moshi 1.4.0, ason 1.1.0.

I found one worthy related article from 2015. It’s compares old versions of gson and jackson and it does not cover moshi and ason.

how I am going to test

I experimented on parsing small (6kb) and big (973kb, slow page!) jsons.

Small JSON consists of list of small objects. Small object consists of 4 simple fields and one list.

Big JSON consists of list of big objects. Big object consists of 19 simple fields and four lists.

I recorded 2 parameters: parsing time and number of GC calls while parsing. Less is better for both.

To track GC calls I used my friends’ GC calls tracker.

testing methodology

Open app.
Run parsing (for example small JSON with gson) 4 times.
Throw away first result.
Find average value for 2–4 runs.
Close app and remove app from recent list.

methods / fields count

It’s worth to mention, due to 65k limit:

        | methods count | fields count
-------------------------------------     
gson    | 1030          | 405
moshi   | 535           | 238
jackson | 6724          | 1756
ason    | 89            | 6

small json parsing

Let’s parse small JSON on 4.4 emulator:

4.4.2   | time / gc
-------------------
gson    | 1124 / 76 
jackson | 840  / 36
moshi   | 2198 / 38
ason    | 3343 / 193

6.0.1 real device (lenovo vibe x3):

6.0.1   | time / gc
--------------------
gson    | 1024 / 3
jackson | 913  / 1
moshi   | 2092 / 2
ason    | 6225 / 14

big JSON parsing

Parsing big JSON on 4.4.2 emulator:

4.4.2   | time / gc
--------------------
gson    | 1837 / 63
jackson | 1536 / 41
moshi   | 2978 / 87
ason    | 1745 / 88

6.0.1 real device (lenovo vibe x3):

6.0.1   | time / gc
--------------------
gson    | 1988 / 5
jackson | 1902 / 4
moshi   | 4611 / 9
ason    | 1373 / 4

Let’s stop here. Ason is far more better than jackson. Moshi shows worst result. I also tried 5.1 emulator and another 6.0 emulator and get similar time ratio. 7.0 emulator gets me another picture:

7.0     | time / gc
--------------------
gson    | 505  / 9
jackson | 327  / 6
moshi   | 692  / 13
ason    | 862  / 17

So ason performance varies between platforms, from fastest to slowest.

conclusion

jackson:
pros: fasters, triggers GC least, most customazible
cons: 6.7k methods (can be reduced by Proguard), API not so friendly

gson:
pros: fast enough, most popular (10k stars on github), pretty API, small
cons: relatively slow, trigger GC relatively more

There is no reasons for me to use moshi or ason based on this comparation: they are slower almost in each test.

Links

Sources on Github
Apk to play with