Smile Data Format
"Smile" is a binary data format that defines a binary equivalent of standard JSON data format.
Design documentation includes:
Format specification describes format itself; how it works and what a compliant parser/generator implementations needs to do.
Design goals explains rationale for design decisions concerning specification.
Jackson developer mailing list is also a good resource regarding the first complete Java-based implementation
Implementations, frameworks that support Smile
Jackson JSON processor has full Smile support, including streaming access, data binding and tree model (i.e. parity with textual JSON)
libsmile is a work-in-progress C-library for reading and writing Smile data.
Elastic Search supports Smile as one of input/output formats
Protostuff project supports Smile both as a low-level data format, and as format used for RPC.