Enhanced version of python-cjson 1.0.3 has been released. It's numbered 1.0.3x, where x stands for eXtension. The main improvement is the ability to extend the JSON encoder and decoder with extensions functions to serialize/unserialize objects not in the original JSON specification. This is achieved without sacrificing the speed and stability of the original implementation. Please send bug reports to python@cx.hu and do not contact the original author (Dan Pascu) about this version. Download and more information: http://cx.hu/python-cjson/ Example to encode/decode python date and datetime objects as JavaScript Date objects: import re import cjson import datetime # Encoding Date objects: def dateEncoder(d): assert isinstance(d, datetime.date) return 'new Date(Date.UTC(%d,%d,%d))'%(d.year, d.month, d.day) json=cjson.encode([1,datetime.date(2007,1,2),2], extension=dateEncoder) assert json=='[1, new Date(Date.UTC(2007,1,2)), 2]' # Decoding Date objects: re_date=re.compile('^new\sDate\(Date\.UTC\(.*?\)\)') def dateDecoder(json,idx): json=json[idx:] m=re_date.match(json) if not m: raise 'cannot parse JSON string as Date object: %s'%json[idx:] args=cjson.decode('[%s]'%json[18:m.end()-2]) dt=datetime.date(*args) return (dt,m.end()) # must return (object, character_count) tuple data=cjson.decode('[1, new Date(Date.UTC(2007,1,2)), 2]', extension=dateDecoder) assert data==[1,datetime.date(2007,1,2),2]