JSON (JavaScript Object Notation) is an open standard file format and data interchange format that uses human-readable text to store and transmit data objects consisting of attribute–value pairs, arrays, and scalar data. It is often used for serializing structured data and exchanging it over a network, typically between a server and web applications. It is based upon JavaScript syntax but is distinct from it. Some JavaScript is not JSON. Property names must be double-quoted strings and trailing commas are forbidden. Leading zeros are also prohibited because a leading 0 indicates an octal number in JavaScript and JSON doesn't support octal numbers.

JSON is designed specifically for data interchange. Compared to XML, JSON is faster. JSON encoding is terse, which requires less bytes for transit. JSON parsers are also less complex, which requires less processing time and memory overhead.