# rei-cpp > [!warning] > This is a work in progress, not stable and the API might change. A C++ JSON library. ## Example ```cpp #include "rei-json/json.h" #include int main() { auto objectJson = rei::json::JsonObject{}; objectJson .set("keyPositiveNumber", 12) .set("keyNegativeNumber", -13) .set("keyBooleanTrue", true) .set("keyBooleanFalse", false) .set("keyString", "YEP") .set("keyEmptyString", "") .setNull("keyNull"); rei::json::JsonObject obj{}; obj.set("keyNumberOnObject", 42); rei::json::JsonArray array{}; array.push(42); array.push("elemString"); array.push(""); array.push(true); array.push(false); array.pushNull(); objectJson.set("keyObject", std::move(obj)); objectJson.set("keyArray", std::move(array)); auto newJsonString = rei::json::toString(objectJson); std::println("{}\n", newJsonString); return 0; } ```