Copyright(c) 2014 Milo Yip (miloyip@gmail.com)

This benchmark evaluates the performance of 20 open-source C/C++ JSON parser/generator libraries. Performance means speed, memory, and code size.

Performance of JSON parsing/generation may be critical for server-side applications, mobile/embedded systems, or any application that requires processing of large size or number of JSONs. Native (C/C++) libraries are important because they should provide the best possible performance, while other languages may create bindings of native libraries.

The results show that several performance measurements varies in a large scales among libraries. For example, the parsing time can be over 100 times. These differences came from many factors, including design and implementation details. For example, memory allocation strategies, design of variant type for JSON, number-string conversions, etc.

This benchmark may be useful for optimizing existing libraries and developing new, high-performance libraries.

The original author (Milo Yip) of this benchmark is also the primary author of RapidJSON.

Although the development of benchmark is tried to be as objective and fair as possible, every benchmarks have their drawbacks, and are limited to particular testing procedures, datasets and platforms. And also, this benchmark does not compare additional features that a library may support, or the user-friendliness of APIs, securities, cross-platform, etc. The author encourage users to benchmarks with their own data sets and platforms.

All benchmarks contain the following measurements:

Currently 20 libraries are successfully benchmarked. They are listed in alphabetic order:

Libraries with Git repository are included as submodule in thirdparty path. Other libraries are add as files in thirdparty path.

All libraries are latest version on 8 Sep 2014. The exact commit of submodule can be navigated at here.

To measure the overheads of the benchmark process, a strdup test is added for comparison. It simply allocate and copy the input string in Parse and Stringify benchmark.

Besides, some libraries was tried to integrated in this benchmark but failed:

All tested JSON data are in UTF-8.

The benchmark program reads data/data.txt which contains file names of JSON to be tested.

1. Execute git submodule update --init to download all submodules (libraries).
2. Obtain premake4.
3. Copy premake4 executable to build/ path (or system path).
4. Run premake.bat or premake.sh in build/
5. On Windows, build the solution at build/vs2008/ or /vs2010/.
6. On other platforms, run GNU make -f benchmark.make config=release32 && make -f nativejson.make (or release64) at build/gmake/
7. Optional: run buuild/machine.sh for UNIX or CYGWIN to use CPU info to generate prefix of result filename.
8. Run the nativejson_release_... executable is generated at bin/
9. The results in CSV format will be written to result/.
10. Run GNU make in result/ to generate results in HTML.

1. How to add a library?

   Use submodule add https://...xxx.git thirdparty/xxx to add the libary's repository as a submobule. If that is not possible, just copy the files into 'thirdparty/xxx'.

   For C libary, add a xxx_all.c in src/cjsonlibs, which #include all the necessary .c files of the library. And then create a tests/xxxtest.cpp.

   For C++ library, just need to create a tests/xxxtest.cpp, which #include all the necessary .cpp files of the library.

   You may find a existing library which similar to your case as a start of implementing tests/xxxtest.cpp.

• Basic benchmarks for miscellaneous C++ JSON parsers and generators by Mateusz Loskot (Jun 2013)

• Casablanca

• json spirit

• JsonCpp

• libjson

• rapidjson

• QJsonDocument

• JSON Parser Benchmarking by Chad Austin (Jan 2013)

• sajson

• RapidJSON

• vjson (Replaced by gason)

• YAJL

• Jansson