Note
Do not start Geppetto like this in a production environment! Running Geppetto as root is dangerous!
Inside your virtualenv set the environmnent GEPPETTO_ENV and start the server:
$ export GEPETTO_ENV=dev
$ .env/bin/python server.py
* Running on http://127.0.0.1:5000/
* Restarting with reloader
Now you interact with the API on 127.0.0.1:5000. See Usage how to use the API and how to toggle GPIO pins.