Add Authfu with Auth.js v5

Before you begin

Create an app in the Authfu console and register the callback URL your framework uses. For Auth.js, that URL ends in /api/auth/callback/authfu.

AUTHFU_CLIENT_ID=...        # from the Authfu console
AUTHFU_CLIENT_SECRET=...    # from the Authfu console
AUTHFU_ISSUER=https://authfu.app   # optional; use http://localhost:3000 against a local provider

1. Install the packages

   Install the Auth.js v5 beta and the Authfu provider package.

   npm install next-auth@beta @authfu/next

2. Configure Auth.js

   Create the root auth module. With the SDK, credentials are read from the environment variables above.

   Authfu SDKProvider object

   // auth.ts
   import NextAuth from "next-auth"
   import { Authfu } from "@authfu/next"
   export const { handlers, auth, signIn, signOut } = NextAuth({ providers: [Authfu()] })

3. Add the route handler

   Expose the handlers from the App Router catch-all route.

   // app/api/auth/[...nextauth]/route.ts
   import { handlers } from "@/auth"
   export const { GET, POST } = handlers

What happens next

Auth.js handles your application session. Authfu handles hosted sign-in: the user enters an email, completes two-factor first when enabled, then receives a single-use magic link and returns to your callback.