Ngrok is used to create a public HTTP tunnel that allows Twilio servers to reach specific requests such as SMS, voice calls and other services. A Twilio account and ngrok account are required for this tutorial. The script uses Flask and the Twilio Server-Side SDK to receive an automatic "text back" message after sending a custom SMS message to a Twilio number. To set up the project, a phone number is purchased, a Python script is created to route SMS messages using POST & GET API requests, ngrok is installed and configured, and the phone number is linked to the webhook. The project can be tested by sending a message to the Twilio number and receiving an automatic response.