If you are using the Rasa API, the “sender” is used to distinguish between conversations… for example, we have an API that processes a queue of messages to send to RASA. We use something like this to forward to Rasa (I’ve removed exception handling code to make it easier to understand):
CHATBOT = "http://localhost:5005/webhooks/rest/webhook"
payload = '{"sender": "' + user + '", "message": "' + message + '"}'
r = requests.post(CHATBOT, data=payload).encode('utf-8')
response = json.loads(r.content)
If you look in the rasa.conversations collection (mongoDB), there are separate entries for each sender.