Send an SMS Message During a Phone Call with Ruby and Sinatra

This tutorial shows how to use Twilio's Programmable Voice and SMS APIs with Ruby and Sinatra to send a text message during a phone call. The process involves setting up a Twilio account, creating a Sinatra app that accepts incoming calls, sends an SMS reply, and handles exceptions for landline callers. The code uses the Twilio Ruby helper library and leverages environment variables to manage secret keys. After setting up ngrok for public access, configuring Twilio's phone number to use the app, and sending an initial message, the app can be modified to track delivery status, create conference calls, or handle exceptions for landline callers.