The Twilio App Monitor is a tool that logs errors and sends notifications when issues occur with Twilio-powered applications. The app monitor can be set up to send SMS alerts using webhooks, allowing developers to receive real-time notifications about errors without relying on email. To demonstrate this, an example application was built using Python and Flask, which receives HTTP POST requests from the App Monitor Trigger and sends an SMS message using the Twilio REST API. The application uses a webhook trigger to receive error information and can be customized to send messages with specific parameters, such as error codes and descriptions. By setting up this system, developers can ensure that their applications are always aware of any issues and can take swift action to resolve them.