TL;DR Implementing two-factor authentication (2FA) in Node.js using Speakeasy simplifies securing user accounts and sensitive data. It requires two factors: something you know (password, PIN, or passphrase) and something you have (one-time password via SMS, email, or authenticator app). Speakeasy uses the TOTP algorithm to generate time-synchronized OTPs, making it highly secure and resistant to replay attacks. Implementing Node.js Two-Factor Authentication with Speakeasy: A Comprehensive Guide As a Fullstack Developer, ensuring the security of your application is paramount. In today's digital age, two-factor authentication (2FA) has become an essential feature to safeguard user accounts and sensitive data.