CatCorner22 Authentication Integrations
You are an expert in authentication for Vercel-deployed applications — covering Clerk (native Vercel Marketplace integration), Descope, and Auth0.
Clerk (Recommended — Native Marketplace Integration)
Clerk is a native Vercel Marketplace integration with auto-provisioned environment variables and unified billing. Current SDK: @clerk/nextjs v7 (Core 3, March 2026).
Install via Marketplace
# Install Clerk from Vercel Marketplace (auto-provisions env vars)
vercel integration add clerk
Auto-provisioned environment variables:
CLERK_SECRET_KEY— server-side API keyNEXT_PUBLIC_CLERK_PUBLISHABLE_KEY— client-side publishable key
SDK Setup
# Install the Clerk Next.js SDK
npm install @clerk/nextjs
Middleware Configuration
// middleware.ts
import { clerkMiddleware } from "@clerk/nextjs/server";
export default clerkMiddleware();
export const config = {
matcher: [
// Skip Next.js internals and static files
"/((?!_next|[^?]*\\.(?:html?|css|js(?!on)|jpe?g|webp|png|gif|svg|ttf|woff2?|ico|csv|docx?|xlsx?|zip|webmanifest)).*)",
// Always run for API routes
"/(api|trpc)(.*)",
],
};
Protect Routes
// middleware.ts — protect specific routes
import { clerkMiddleware, createRouteMatcher } from "@clerk/nextjs/server";
const isProtectedRoute = createRouteMatcher(["/dashboard(.*)", "/api(.*)"]);
export default clerkMiddleware(async (auth, req) => {
if (isProtectedRoute(req)) {
await auth.protect();
}
});
Frontend API Proxy (Core 3)
Proxy Clerk's Frontend API through your own domain to avoid third-party requests:
// middleware.ts
export default clerkMiddleware({
frontendApiProxy: { enabled: true },
});
Provider Setup
// app/layout.tsx
import { ClerkProvider } from "@clerk/nextjs";
export default function RootLayout({
children,
}: {
children: React.ReactNode;
}) {
return (
<ClerkProvider>
<html lang="en">
<body>{children}</body>
</html>
</ClerkProvider>
);
}
Sign-In and Sign-Up Pages
// app/sign-in/[[...sign-in]]/page.tsx
import { SignIn } from "@clerk/nextjs";
export default function Page() {
return <SignIn />;
}
// app/sign-up/[[...sign-up]]/page.tsx
import { SignUp } from "@clerk/nextjs";
export default function Page() {
return <SignUp />;
}
Add routing env vars to .env.local:
NEXT_PUBLIC_CLERK_SIGN_IN_URL=/sign-in
NEXT_PUBLIC_CLERK_SIGN_UP_URL=/sign-up
Access User Data
// Server component
import { currentUser } from "@clerk/nextjs/server";
export default async function Page() {
const user = await currentUser();
return <p>Hello, {user?.firstName}</p>;
}
// Client component
"use client";
import { useUser } from "@clerk/nextjs";
export default function UserGreeting() {
const { user, isLoaded } = useUser();
if (!isLoaded) return null;
return <p>Hello, {user?.firstName}</p>;
}
API Route Protection
// app/api/protected/route.ts
import { auth } from "@clerk/nextjs/server";
export async function GET() {
const { userId } = await auth();
if (!userId) {
return Response.json({ error: "Unauthorized" }, { status: 401 });
}
return Response.json({ userId });
}
Descope
Descope is available on the Vercel Marketplace with native integration support.
Install via Marketplace
vercel integration add descope
SDK Setup
npm install @descope/nextjs-sdk
Provider and Middleware
// app/layout.tsx
import { AuthProvider } from "@descope/nextjs-sdk";
export default function RootLayout({
children,
}: {
children: React.ReactNode;
}) {
return (
<AuthProvider projectId={process.env.NEXT_PUBLIC_DESCOPE_PROJECT_ID!}>
<html lang="en">
<body>{children}</body>
</html>
</AuthProvider>
);
}
// middleware.ts
import { authMiddleware } from "@descope/nextjs-sdk/server";
export default authMiddleware({
projectId: process.env.DESCOPE_PROJECT_ID!,
publicRoutes: ["/", "/sign-in"],
});
Sign-In Flow
"use client";
import { Descope } from "@descope/nextjs-sdk";
export default function SignInPage() {
return <Descope flowId="sign-up-or-in" />;
}
Auth0
Auth0 provides a mature authentication platform with extensive identity provider support.
SDK Setup
npm install @auth0/nextjs-auth0
Configuration
// lib/auth0.ts
import { Auth0Client } from "@auth0/nextjs-auth0/server";
export const auth0 = new Auth0Client();
Required environment variables:
AUTH0_SECRET=<random-secret>
AUTH0_BASE_URL=http://localhost:3000
AUTH0_ISSUER_BASE_URL=https://your-tenant.auth0.com
AUTH0_CLIENT_ID=<client-id>
AUTH0_CLIENT_SECRET=<client-secret>
Middleware
// middleware.ts
import { auth0 } from "@/lib/auth0";
import { NextRequest, NextResponse } from "next/server";
export async function middleware(request: NextRequest) {
return await auth0.middleware(request);
}
export const config = {
matcher: [
"/((?!_next/static|_next/image|favicon.ico|sitemap.xml|robots.txt).*)",
],
};
Access Session Data
// Server component
import { auth0 } from "@/lib/auth0";
export default async function Page() {
const session = await auth0.getSession();
return session ? (
<p>Hello, {session.user.name}</p>
) : (
<a href="/auth/login">Log in</a>
);
}
Auth.js (NextAuth v5)
Prefer Clerk Marketplace for new apps. Use this section for existing Auth.js / next-auth projects.
npm install next-auth@beta
// auth.ts
import NextAuth from "next-auth"
export const { auth, handlers, signIn, signOut } = NextAuth({
providers: [/* … */],
})
// app/api/auth/[...nextauth]/route.ts
import { handlers } from "@/auth"
export const { GET, POST } = handlers
Migrate v4 getServerSession(authOptions) → await auth(). Generate AUTH_SECRET in the bootstrap flow (openssl rand -base64 32). See https://authjs.dev/getting-started/installation?framework=Next.js
Decision Matrix
| Need | Recommended | Why |
|---|---|---|
| Fastest setup on Vercel | Clerk | Native Marketplace, auto-provisioned env vars |
| Existing next-auth / Auth.js app | Auth.js v5 | auth() helper; do not rewrite to Clerk unless asked |
| Passwordless / social login flows | Descope | Visual flow builder, Marketplace native |
| Enterprise SSO / SAML / multi-tenant | Auth0 | Deep enterprise identity support |
| Pre-built UI components | Clerk | Drop-in <SignIn />, <UserButton /> |
| Vercel unified billing | Clerk or Descope | Both are native Marketplace integrations |
Clerk Core 3 Breaking Changes (March 2026)
Clerk provides an upgrade CLI that scans your codebase and applies codemods: npx @clerk/upgrade. Requires Node.js 20.9.0+.
auth()is async — always useconst { userId } = await auth(), not synchronousauth.protect()moved — useawait auth.protect()directly, not from the return value ofauth()clerkClient()is async — useawait clerkClient()in middleware handlersauthMiddleware()removed — migrate toclerkMiddleware()@clerk/typesdeprecated — import types from SDK subpath exports:import type { UserResource } from '@clerk/react/types'(works from any SDK package)ClerkProviderno longer forces dynamic rendering — pass thedynamicprop if needed- Cache components — when using Next.js cache components, place
<ClerkProvider>inside<body>, not wrapping<html> - Satellite domains — new
satelliteAutoSyncoption skips handshake redirects when no session cookies exist - Smaller bundles — React is now shared across framework SDKs (~50KB gzipped savings)
- Better offline handling —
getToken()now correctly distinguishes signed-out from offline states
Cross-References
- Marketplace install and env var provisioning →
⤳ skill: marketplace - Middleware routing patterns →
⤳ skill: routing-middleware - Environment variable management →
⤳ skill: env-vars