Fetch custom payload send to RASA server

Since past few days, I am struggling with the problem to fetch the payload sent to RASA server.

For example: I sent the following payload as a POST request to RASA server:

{ “sender”: “shaurya”, “message”: “What is LLM?” }

I want to fetch this complete payload in custom actions so that I could use the sender name, which is “shaurya” in this case, and run some database queries to generate custom responses. I am able to fetch “sender_id” but not the name. Can anyone help me to get the solution for this?