Building Expedited Two-Factor Authentication into Angular Apps with Authy. To add "remember me" functionality to an Angular Universal + Node.js application, you can use the Angular TransferState object and a security cookie to identify returning users. This allows returning users to log into the application with a single tap on the Authy app, bypassing the step of re-entering their credentials while maintaining the added security of two-factor authentication. The process involves setting up an Authy account, generating an API key and user ID, creating an encrypted cookie, and implementing a "remember me" control on the login page. The application flow can be seen in a diagram, and testing the completed application shows that it works as described.