How to Implement TOTP-Based 2FA in .NET the Right Way youtube.com

Your login flow is not complete without 2FA. In this video, I show you how to implement TOTP-based two-factor authentication in .NET from scratch.

We walk through how time-based one-time passwords work, how to generate and share a secret using a QR code, and how to validate codes in your API using a practical .NET implementation. I also cover the production details that matter, like encrypting secrets at rest, handling clock drift, and thinking through recovery flows.

In this video, we cover:

What 2FA and TOTP are, and why they improve application security
How authenticator apps like Google Authenticator and Microsoft Authenticator fit into the flow
Generating a shared secret and encoding it for QR code setup
Building a QR code endpoint in a .NET 10 API
Validating one-time passwords with OTP.NET
Handling verification windows and clock synchronization issues
Why secret keys must be encrypted at rest
What a production-ready 2FA flow still needs, like recovery options and proper secret storage