Why not cash&carry?
This tool will notify you when there is an important spread on ftx spot and futures exchange
You have to setup pushbullet api in order to have notifications.
Python3 and some libs are required in order to work with this script.
pip3 install ftx
pip3 install pushbullet.py
pip3 install ciso8601
python3 finder.py
if you have installed python3 and are under linux you can use the start.sh script