# Header only - JSON for Modern C++
Author: Niels Lohmann

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# Header only

`json.hpp` is the single required file in `single_include/nlohmann` or released here. You need to add

    #include <nlohmann/json.hpp>

    // for convenience
    using json = nlohmann::json;

to the files you want to process JSON and set the necessary switches to enable C++11 (e.g., `-std=c++11` for GCC and Clang).

You can further use file `single_include/nlohmann/json_fwd.hpp` for forward declarations.

November 12, 2025