Adobe AIR file upload response data in complete handler is null while fiddler(web debugger) shows that json is returned as response
Seems like it's a known issue on iOS? Are you trying to do this from iOS?
I ran into the same problem. Instead of using air.Event.COMPLETE, try to use air.DataEvent.UPLOAD_COMPLETE_DATA:
file.addEventListener(air.DataEvent.UPLOAD_COMPLETE_DATA, function(e){ air.Introspector.Console.log(e.data);});