Is data sent to and from an API endpoint on Firebase Functions encrypted?

I've set up a Firebase function that accepts and sends data to a client. I want to be sure that data sent unencrypted (in JSON format, for example { order_amount: float, business_secret_key: string, etc. }) is encrypted just by virtue of the fact that Firebase Functions use the HTTPS protocol? Sorry if this has an obvious answer but I am not an expert in encryption and communication protocols.