How does this compare with ArduinoJson?

[bblanchon]

Hi!

I'm the developer of ArduinoJson.
I'm curious to know how this library differs from it.
Why should someone choose this one over ArduinoJson?

Best Regards,
Benoit

[sandeepmistry]

Hi @bblanchon,

The goal of this library is to be simple to use, and avoid C/C++ concepts that Arduino users are not familiar with.

[bblanchon]

Hi @sandeepmistry,

Thank you for your answer but it doesn't provide any comparison with ArduinoJson, nor any guidance to choose one or the other.

I made my own comparison and benchmark; you can read the article on arduinojson.org
Here is a summary of the article:

Features

JSON support

	ArduinoJson	Arduino_JSON
JSON serialization	✔️	✔️
JSON deserialization	✔️	✔️
Decode UTF-16 literals	✔️	✔️
Comments in JSON input	✔️
Single quotes in JSON input	✔️
Prettified output	✔️
Deserialization error information	✔️

Compatible types

	ArduinoJson	Arduino_JSON
Arduino String	✔️	✔️
Flash strings	✔️	✔️
Arduino streams	✔️
STL string	✔️
STL streams	✔️
long long	✔️

Integration with the C++ language

	ArduinoJson	Arduino_JSON
Access values with []	✔️	✔️
Implicit casts	✔️	✔️
Namespace	✔️
const friendly	✔️
for friendly	✔️
template friendly	✔️
Deserialization error information	✔️
Usable outside of Arduino	✔️

Other features

	ArduinoJson	Arduino_JSON
Thread-safe	✔️	✔️
MessagePack serialization	✔️
MessagePack deserialization	✔️
Stack-only allocation	✔️
Fixed heap allocation	✔️
Zero-copy	✔️

Project information

	ArduinoJson	Arduino_JSON
License	MIT	LGPL
Test coverage	98%	0%
Popularity	4055	21
Documentation	✔️

Performance

Serialize to Serial

	ArduinoJson	Arduino_JSON
Program size	3.6 KB ✔️	7.9 KB
Running time	2.2 ms ✔️	2.3 ms
Heap allocations	0 ✔️	20
RAM usage	426 B ✔️	454 B
Fragmentation	0 % ✔️	1.5 %

Serialize to String

	ArduinoJson	Arduino_JSON
Program size	5.2 KB ✔️	8.0 KB
Running time	2.1 ms	1.9 ms ✔️
Heap allocations	2 ✔️	21
RAM usage	499 B ✔️	534 B
Fragmentation	0 % ✔️	6.21 %

Serialize to char[]

	ArduinoJson	Arduino_JSON
Program size	3.8 KB ✔️	8.2 KB
Running time	1.7 ms ✔️	1.9 ms
Heap allocations	0 ✔️	21
RAM usage	492 B ✔️	522 B
Fragmentation	0 %	0 %

Deserialize from const char*

	ArduinoJson	Arduino_JSON
Program size	4.0 KB ✔️	11 KB
Running time	0.8 ms ✔️	0.9 ms
Heap allocations	0 ✔️	10
RAM usage	449 B ✔️	540 B
Fragmentation	0 %	0%

Deserialize from char[]

	ArduinoJson	Arduino_JSON
Program size	4.1 KB ✔️	11 KB
Running time	0.8 ms ✔️	0.9 ms
Heap allocations	0 ✔️	10
RAM usage	488 B ✔️	540 B
Fragmentation	0 %	0%

Using a char[] enables the zero-copy mode of ArduinoJson, saving a large amount of memory.

Deserialize from Serial

	ArduinoJson	Arduino_JSON
Program size	4.2 KB ✔️	11.3 KB
Running time	2.9 ms ✔️	1004 ms
Heap allocations	0 ✔️	73
RAM usage	387 B ✔️	468 B
Fragmentation	0 % ✔️	3.82 %

Conclusion

• ArduinoJson has many more features than Arduino_JSON.
• ArduinoJson is almost twice smaller than Arduino_JSON.
• ArduinoJson is slightly faster than Arduino_JSON.
• ArduinoJson consumes less RAM than Arduino_JSON (provided that the memory pool is adjusted).
• ArduinoJson doesn't increase memory fragmentation.
• Arduino_JSON is slightly easier to use

Best Regards,
Benoit