This application allows users to register their phone numbers to receive notifications when a specific text message is received. The notification includes a pre-set message that can be customized by the user. The application uses Python, Flask, and Twilio to send notifications via SMS or voice calls. It also has an endpoint for handling incoming messages from registered users, which can choose to receive either SMS or voice calls. The application can be run on a local server or remotely, and requires no prior setup beyond installing the necessary dependencies and configuring the Twilio account.