py-demjson provides classes and functions for encoding or decoding
data represented in the language-neutral JSON format (which is often
used as a simpler substitute for XML in Ajax web applications). This
implementation tries to be as compliant to the JSON specification (RFC
4627) as possible, while still providing many optional extensions to
allow less restrictive JavaScript syntax. It includes complete Unicode
support, including UTF-32, BOM, and surrogate pair processing. It can
also support JavaScript's NaN and Infinity numeric types as well as
it's 'undefined' type. It also includes a lint-like JSON syntax
validator which tests JSON text for strict compliance to the standard.

WWW: http://deron.meranda.us/python/demjson/