JsonCpp

JSON is a lightweight data-interchange format. It can represent numbers, strings, ordered sequences of values, and collections of name/value pairs.

JsonCpp is a C++ library that allows manipulating JSON values, including serialization and deserialization to and from strings. It can also preserve existing comment in deserialization/serialization steps, making it a convenient format to store user input files.

Project Status

JsonCpp is a mature project in maintenance mode. Our priority is providing a stable, reliable JSON library for the long tail of C++ development.

Current Focus

• Security: Addressing vulnerabilities and fuzzing results.
• Compatibility: Ensuring the library builds without warnings on the latest versions of GCC, Clang, and MSVC.
• Reliability: Fixing regressions and critical logical bugs.

Out of Scope

• Performance: We are not competing with SIMD-accelerated or reflection-based parsers.
• Features: We are generally not accepting requests for new data formats or major API changes.

JsonCpp remains a primary choice for developers who require comment preservation and support for legacy toolchains where modern C++ standards are unavailable. The library is intended to be a reliable dependency that does not require frequent updates or major migration efforts.

A note on backward-compatibility

• 1.y.z (master): Actively maintained. Requires C++11.

• 0.y.z: Legacy support for pre-C++11 compilers. Maintenance is limited to critical security fixes.

• 00.11.z: Discontinued.

Major versions maintain binary compatibility. Critical security fixes are accepted for both the master and 0.y.z branches.

Integration

Note

Package manager ports (vcpkg, Conan, etc.) are community-maintained. Please report outdated versions or missing generators to their respective repositories.

vcpkg

Add jsoncpp to your vcpkg.json manifest:

{
  "dependencies": ["jsoncpp"]
}

Or install via classic mode: vcpkg install jsoncpp.

Conan

conan install --requires="jsoncpp/[*]" --build=missing

If you are using a conanfile.txt in a Conan 2 project, ensure you use the appropriate generators:

[requires]
jsoncpp/[*]

[generators]
CMakeToolchain
CMakeDeps

Meson

meson wrap install jsoncpp

Amalgamated source

Note

This approach may be outdated.

For projects requiring a single-header approach, see the Wiki entry.

Documentation

Documentation is generated via Doxygen. Additional information is available on the Project Wiki.

License

JsonCpp is licensed under the MIT license, or public domain where recognized. See LICENSE for details.