Guide: Implementing WebAuthn for React 19 Apps Using Next.js 17 and SimpleWebAuthn 7.0 WebAuthn (Web Authentication API) is a standards-based API that enables strong, passwordless authentication using hardware security keys, biometrics (like TouchID, FaceID), or device-based authenticators. For React 19 apps built with Next.js 17, pairing WebAuthn with SimpleWebAuthn 7.0 — a lightweight library that abstracts away complex WebAuthn spec details — simplifies implementation drastically. This guide walks through every step, from project setup to production-ready authentication flows.…