For most programs that just need to encode or decode JSON data, you should probably use the built-in json module in the standard Python library. But demjson still has advantages for certain niche uses.

History

I wrote demjson before the Python language had any built-in JSON support in its standard library. At the time, there were only a handful of third-party libraries, but most had serious deficiencies and none were completely compliant with the RFC specification. Furthermore the best of those required a compiled C extension, which was not suitable for all environments. Thus the birth of demjson.

Since then Python has added JSON support into its standard library — which was actually an absorption of the “simplejson” module, written by Bob Ippolito, and which had by then been fixed to remove bugs and improve RFC conformance.

Things demjson can do better

However demjson may still be useful: