With the IBM Watson Twilio Add-on, developers can now analyze the sentiment of text messages sent to their Twilio numbers. A Flask app was built to demonstrate how to use this add-on, which uses the Twilio Python library and ngrok to send requests to a publicly accessible URL. The application receives an HTTP request from Twilio containing the message received by the Twilio number, as well as sentiment analysis data provided by IBM Watson, including a score indicating whether the sentiment is positive or negative. The Flask app then generates a response based on this sentiment, which can be used to improve customer experience or other applications.