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JsonAPI is a C++ wrapper library for jansson JSON C library. It is well-suited to run on microcontrollers but can also run on the desktop.


The JsonAPI uses the Stratify Labs API framework which is based on the following design principles

  • Thread Local Error Contexts
  • Method Chaining
  • Filesystem Inspired Abstraction
  • Strong Arguments
  • RAII Everywhere

More details of these principles are available at


The JsonAPI library is designed to be a CMake sub-project. To build, please use one of these projects:


Under the hood, all memory management is handled by jansson. The C++ objects just hold pointers to the jansson handled memory. So all objects should be passed by value rather than by reference.

You can easily create a JSON object using method chaining:

#include <json.hpp>
//create an objectJsonObject object = JsonObject()                      .insert("string", JsonString("string"))                      .insert("integerString", JsonString("100"))                      .insert("integer", JsonInteger(10))                      .insert("integerZero", JsonInteger(0))                      .insert("real", JsonReal(2.2f))                      .insert("realString", JsonString("2.2f"))                      .insert("realZero", JsonReal(0.0f))                      .insert("true", JsonTrue())                      .insert("false", JsonFalse())                      .insert("null", JsonNull())                      .insert("trueString", JsonString("true"))                      .insert(                        "array",                        JsonArray()                          .append(JsonString("string"))                          .append(JsonInteger(5))                          .append(JsonReal(2.5f))                          .append(JsonTrue())                          .append(JsonFalse())                          .append(JsonNull()))
//access an objectconst auto str ="string").to_cstring()const auto b ="true").to_bool()

You can load and save JSON documents using JsonDocument.

#include <fs.hpp>#include <json.hpp>
//using the object aboveJsonDocument().save(object, File(File::IsOverwrite::yes, "object.json"))JsonObject loaded_object = JsonDocument().load(File("object.json"))