msgpack for C/C++
It's like JSON but smaller and faster.
MessagePack is an efficient binary serialization format, which lets you exchange data among multiple languages like JSON, except that it's faster and smaller. Small integers are encoded into a single byte and short strings require only one extra byte in addition to the strings themselves.
You can get additional information including the tutorial on the wiki.
Here's the list of great contributors.
msgpack-c is licensed under the Boost Software License, Version 1.0. See
LICENSE_1_0.txt file for details.