JSON or JavaScript Object Notification is a well-known lightweight data interchange format, which is easier for the humans to read and write and for the machines to conjugate and generate. This format is based on the subset of the JavaScript Programming Language, which was introduced in December 1999 in the third edition of standard ECMA-262. The most advantageous quality of JSON is that it is completely language independent.

The recent release of PHP 5.2.0 includes a default extension that helps to convert PHP values from and to JSON format. The homepage of JSON contains four significant PHP libraries that are available for downloading as well as look stable and maintained. These libraries include the lib, the JSON lib, Zend JSON lib and the JSONRPC.

The lib library was originally written by Omar Kilani and now it is a part of PHP. This is the only library that is written in C language and it provides advantages in terms of speed execution.

The JSON library was originally written by M. Migurski and now it is an official part of PEAR. This was the first lib implemented by JSON in PHP and is association with PEAR has led to guaranteed quality and stability in coding.

The third JSON library i.e. ZEND JSON lib is now the official part of the ZEND framework. It is one of the most recent libraries backed by ZEND behind the PHP engine. It is also a part of the framework of components, which are regarded as the trendiest nowadays and seek a bright future.

The fourth JSON PHP library is JSONRPC lib, which is an extension of PHP-XMLRPC lib. It was built to provide JSON-RPC protocol’s support to the existing XMLRPC implementation.