Are there any Tools / Chrome plugins like "Advanced REST Plugin" for Chrome that I can use to Test Twisted RPC JSON calls?
Or do I have to write some Python code to do this?
When it comes to testing, you sould always use code, so that if you change something in the future or if you have to fix a bug, testing your changes will be a matter of seconds:
python mytestsuite.py
Tools to Test RPC twisted calls?