Lightweight data-interchange format, readable by humans and machines. Used to exchange objects from within programs across the open internet without tying them to language-specific implementations (i.e. converting objects from Ruby to PHP to Objective-C to….) by converting objects into arrays, dictionaries, and primitives.
Built on two structures:
The entire JSON is a dictionary.
Dictionaries are represented with curly braces. Arrays are represented with square brackets.
A colon pairs a key and an object.
See here for an excellent example.