How to Add Two-Factor Authentication (2FA) to Your Node.JS Web Apps

This tutorial teaches developers how to implement two-factor authentication (2FA) in a web app using Node.js and the Vonage Verify API, making it more secure for users. To start, a web app is set up with an Express.js framework, and a simple form is created for users to input their phone number. The backend code receives the value from the form via POST and uses the Nexmo module to send a 4-digit PIN code to the user's phone number. Once the PIN code is received, the user enters it into another form field on a new page, which checks the PIN code with the Nexmo Verify API to verify its correctness. If successful, the app renders an "Account Verified" message. The tutorial emphasizes the importance of handling all error statuses in the app UI for better user experiences.