In this article, the author guides users through building an application that verifies user identity using Twilio Verify's SMS feature. The process involves setting up a Twilio account, creating a new Twilio Verify service, and configuring it to send and receive SMS messages. The author then builds a frontend application in JavaScript and HTML, which sends the user's phone number to the backend endpoint `/send-notification` for verification. After receiving the phone number, the backend endpoint creates a verification check using Twilio Verify's API. When the user submits their OTP, the backend endpoint verifies it against the stored verification code and returns a response with the status of the verification check. The article concludes by testing out the application and deploying the functions to a publicly accessible URL for use in production.