This code produces the wrong result

import cjson
cjson.decode(cjson.encode('/'))

It produces '\\/', it should produce '/'

using
/usr/lib/pymodules/python2.7/cjson.so
cjson version 1.0.5-4build1

cjson is a third party module and not part of Python's standard library. Please report the error to the author of the cjson package. 

Python 2.7 has a builtin json encoder and decoder. The package is called 'json'. http://docs.python.org/2.7/library/json.html#module-json

This works fine with the standard json module.
>>> json.loads(json.dumps('/'))
'/'

FWIW 'json' also has C accelerations.