ease/doc/html/program_options.html) |  The library allows to obtain program options, that is (name, value) pairs from the user, via conventional methods such as command line, config file, and environment variables.  |  [ BSL-1.0 ](https://www.boost.org/LICENSE_1_0.txt) |   
[ CLI11 ](https://github.com/CLIUtils/CLI11) |  A C++11 command line parser that provides a rich feature set with a simple and intuitive interface.  |  BSD-3-Clause  |  header-only; cmake, meson, vcpkg   
[ clipp ](https://github.com/muellan/clipp) |  Powerful & Expressive Argument Parsing for Modern C++.  |  MIT  |  header-only; cmake, vcpkg   
[ cmd_line_parser ](https://github.com/jermp/cmd_line_parser) |  Command line parser for C++17.  |  MIT  |  header-only; cmake   
[ cmdlime ](https://github.com/kamchatka-volcano/cmdlime) |  A C++17 library for command-line parsing that provides a concise, declarative interface with support for sub-commands, validators, and the ability to choose either the GNU, POSIX, or X11 command-line options format.  |  MS-PL  |  cmake   
[ cxxopts ](https://github.com/jarro2783/cxxopts) |  A lightweight C++11/C++17 command-line arguments parser, supporting the standard GNU style syntax for options.  |  MIT  |  header-only; bazel, cmake   
[ fire-hpp ](https://github.com/kongaskristjan/fire-hpp) |  Create fully functional CLIs using function signatures.  |  BSL-1.0  |  header-only; cmake   
[ flags ](https://github.com/sailormoon/flags) |  Simple, extensible C++17 argument parser.  |  [ Unlicense ](http://unlicense.org/) |  header-only; cmake   
[ gflags ](https://gflags.github.io/gflags/) |  A library that implements command-line flags processing. It includes built-in support for standard types such as string and the ability to define flags in the source file in which they are used.  |  BSD  |  cmake   
[ structopt ](https://github.com/p-ranav/structopt) |  Parse command line arguments by defining a struct.  |  MIT  |  header-only; cmake   
[ tclap ](https://sourceforge.net/projects/tclap/) |  A simple C++ template library for parsing command line arguments. The library provides a simple, flexible object-oriented interface.  |  MIT  |  cmake   
  
CSS

Library  |  Description  |  License  |  Configuration   
---|---|---|---  
[ mycss ](https://github.com/lexborisov/mycss) |  CSS Parser  |  |   
  
HOCON

Library  |  Description  |  License  |  Configuration   
---|---|---|---  
[ cpp-hocon ](https://github.com/puppetlabs/cpp-hocon/tree/master/lib/src) |  A C++ implementation of the HOCON format developed by Pupplet.  |  |   
  
JSON

Library  |  Description  |  License  |  Configuration   
---|---|---|---  
[ ArduinoJson ](https://github.com/bblanchon/ArduinoJson) |  C++98/11/14/17 JSON library for Arduino, IoT and embedded C++  |  MIT  |  cmake   
[ Boost.JSON ](https://www.boost.org/doc/libs/release/libs/json/doc/html/index.html) |  The JSON parsing, serialization, and DOM in C++11/17  |  [ BSL-1.0 ](https://www.boost.org/LICENSE_1_0.txt) |   
[ cajun-jsonapi ](https://sourceforge.net/projects/cajun-jsonapi/) |  A C++ API for the JSON with an emphasis on an intuitive, concise interface that mimic standard C++ as closely as possible.  |  |  make   
[ DAW JSON Link ](https://github.com/beached/daw_json_link) |  A C++17 library providing static C++ bindings with type checking allowing of parsing directly to user data structures without library allocation, push/pull modes, allocator support, constexpr  |  BSL 1.0  |  cmake   
[ jansson ](https://github.com/akheron/jansson) |  A C library for encoding, decoding and manipulating JSON data with UTF-8 support  |  MIT  |  cmake, make   
[ jeayeson ](https://github.com/jeaye/jeayeson) |  A very sane C++14 JSON library  |  BSD-3  |  header-only   
[ jios ](https://github.com/castedo/jios) |  JSON Input Output Streams  |  MIT  |  cmake   
[ JOST ](http://ddsbench.svn.sourceforge.net/viewvc/ddsbench/trunk/jost/) |  |  |   
[ json ](https://github.com/nlohmann/json) |  Niels Lohmann JSON f