#include using json = nlohmann::json; int main() { // a JSON text auto text = R"( { "Image": { "Width": 800, "Height": 600, "Title": "View from 15th Floor", "Thumbnail": { "Url": "http://www.example.com/image/481989943", "Height": 125, "Width": 100 }, "Animated" : false, "IDs": [116, 943, 234, 38793] } } )"; // fill a stream with JSON text std::stringstream ss; ss << text; // create JSON from stream json j_complete(ss); // deprecated! // shall be replaced by: json j_complete = json::parse(ss); std::cout << std::setw(4) << j_complete << "\n\n"; // define parser callback json::parser_callback_t cb = [](int depth, json::parse_event_t event, json & parsed) { // skip object elements with key "Thumbnail" if (event == json::parse_event_t::key and parsed == json("Thumbnail")) { return false; } else { return true; } }; // fill a stream with JSON text ss.clear(); ss << text; // create JSON from stream (with callback) json j_filtered(ss, cb); // shall be replaced by: json j_filtered = json::parse(ss, cb); std::cout << std::setw(4) << j_filtered << '\n'; }