Connect ESP8266 to MIT APP with bluetooth? Wifi? other?

I have an ESP8266 with some sensors and relays working on it.
I am now trying to create a MIT APP that will allow me to enter values on my android telephone and have the relays close for the values as the time in seconds.
I tried using an HM-18 bluetooth and could connect the sample phone app to the bluetooth BUT could not see the bluetooth from the MIT APP.
I am wondering if I should connect via wifi from my phone and the ESP8266?

Hi @henry_Dennig if I don't miss then you can connect ESP8266 with firebase and you can also connect App Inventor with firebase.

Thank you. I have not read about Firebase.