bblanchon/ArduinoJson

ArduinoJson is a C++ JSON library for Arduino and IoT (Internet Of Things).

Features

• JSON decoding (comments are supported)
• JSON encoding (with optional indentation)
• MessagePack
• Elegant API, easy to use
• Fixed memory allocation (zero malloc)
• No data duplication (zero copy)
• Portable (written in C++98, can be used in any C++ project)
• Self-contained (no external dependency)
• Small footprint
• Input and output streams
• 100% code coverage
• Header-only library
• MIT License
• Comprehensive documentation

Compatibility

ArduinoJson works on the following hardware:

• Arduino boards: Uno, Due, Mini, Micro, Yun...
• Espressif chips: ESP8266, ESP32
• WeMos boards: D1, D1 mini, ...
• RedBearLab boards: BLE Nano, BLE Mini, WiFi Micro, LOLIN32...
• Teensy boards
• Intel boards: Edison, Galileo...
• Particle boards: Photon, Electron...
• Texas Instruments boards: MSP430...

ArduinoJson compiles with zero warning on the following compilers, IDEs, and platforms:

• Arduino IDE
• PlatformIO
• Energia
• Visual Micro
• Atmel Studio
• IAR Embedded Workbench
• Atollic TrueSTUDIO
• Keil uVision
• MPLAB X IDE
• GCC
• Clang
• Visual Studio

Quickstart

Deserialization

Here is a program that parses a JSON document with ArduinoJson.

char json[] = "{\"sensor\":\"gps\",\"time\":1351824120,\"data\":[48.756080,2.302038]}";

DynamicJsonDocument doc(1024);
deserializeJson(doc, json);

const char* sensor = doc["sensor"];
long time          = doc["time"];
double latitude    = doc["data"][0];
double longitude   = doc["data"][1];

See the tutorial on arduinojson.org

Serialization

Here is a program that generates a JSON document with ArduinoJson:

DynamicJsonDocument doc(1024);

doc["sensor"] = "gps";
doc["time"]   = 1351824120;

JsonArray data = doc.createNestedArray("data");
data.add(48.756080);
data.add(2.302038);

serializeJson(doc, Serial);
// This prints:
// {"sensor":"gps","time":1351824120,"data":[48.756080,2.302038]}

See the tutorial on arduinojson.org

Documentation

The documentation is available on arduinojson.org, here are some shortcuts:

• The Examples show how to use the library in various situations.
• The API Reference contains the description of each class and function.
• The FAQ has the answer to virtually every question.
• The ArduinoJson Assistant writes programs for you!

Do you like this library? Please star this project on GitHub!

What? You don't like it but you love it? We don't take donations anymore, but we sell a book, so you can help and learn at the same time!