How to Build Passkey Authentication with WebAuthn, Next.js, and NestJS

Passwords are a burden for both users and service providers. Users struggle to remember them, and the risks of phishing and password reuse across multiple sites remain high. Developers must hash and salt passwords, enforce rate limits, and build "forgot password" flows that nobody enjoys.

Fortunately, passkeys address many of these issues. Instead of entering a password, users verify their identity with an authenticator they already use—such as a fingerprint, facial recognition, or a PIN. The authenticator signs a cryptographic challenge using a key stored on the device, and that key is never shared.

This tutorial shows you how to build an app without traditional passwords. The backend is a NestJS API that stores users and their passkeys in PostgreSQL. The frontend is a Next.js app where users sign up and sign in using only an email address and a passkey. You'll use SimpleWebAuthn, a well-maintained TypeScript library that simplifies WebAuthn cryptography and data parsing.

By the end of this article, you'll be equipped to implement passkey registration and authentication for your website and validate passkeys securely on your server. You'll also learn about potential risks and pitfalls that could affect your app or user accounts, and how to mitigate them.

The complete source code is available on GitHub.

Table of Contents

• The Problems with Password-Based Authentication
• How Passkeys Solve These Problems
• Prerequisites
• What Are Passkeys?

(Additional sections continue below.)

via FreeCodeCamp