How do I make a webhook file for receiving sms messages from 3rd party SMS provider?

[samis]

I have been working on an SMS integration between EspoCRM and Bandwidth. The goal of the project is to be able to send and receive SMS messages to clients while using Bandwidth as the 3rd party SMS provider. I already downloaded the official SMS Providers directory from EspoCRM's github and installed the extension. I also have made a customized BandwidthSender that mimics the other prepackaged options SMS Providers offered (Twilio, GatewayAPI, etc) and I configured other files and it successfully connects to Bandwidth. But I still have trouble getting SMS messages to work, and I while I can send messages to Bandwidth, I cannot receive messages from Bandwidth currently, which is bad because we will need to be able to do that to be able to opt-out users if they so choose. I know I need to make a webhook file in the public folder in EspoCRM, but beyond that, I'm lost. Additionally, I'd like to ask, do I have to create a database to keep track of opted-out users, or does EspoCRM have it's own way of taking care of stuff like that I am just not aware of yet?