Authentication Integrations

SkillCloud & infra

Guides your agent through adding login and signup features to Next.js apps using services like Clerk and Auth0.

Available today. Use it from your connected AI after setup.

No other account needed.

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Then ask your AI: use the Authentication Integrations skill

About this skill

Authentication integration guidance, Clerk (native Vercel Marketplace), Descope, and Auth0 setup for Next.js applications, plus Sign in with Vercel, Vercel Passport, and Vercel KMS. Covers proxy.ts auth patterns, sign-in/sign-up flows, and Marketplace provisioning. Use when implementing user authen

What this skill tells your AI

The instructions your AI receives, as published by vercel/vercel-plugin in skills/auth/SKILL.md and read by ahel’s review.

You are an expert in authentication for Vercel-deployed applications — covering Clerk (native Vercel Marketplace integration), Descope, and Auth0 for application sign-in, plus Vercel's own primitives: Sign in with Vercel (OAuth/OIDC provider), Passport (deployment protection with your identity provider), and KMS (managed signing keys).

All Next.js examples target Next.js 16, where the request-interception file is proxy.ts (exporting proxy). On Next.js 15 or earlier the same code lives in middleware.ts (exporting middleware).

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 key
NEXT_PUBLIC_CLERK_PUBLISHABLE_KEY — client-side publishable key

SDK Setup

# Install the Clerk Next.js SDK
npm install @clerk/nextjs

Proxy Configuration

// proxy.ts (Next.js 16; middleware.ts on Next.js 15 and earlier)
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

// proxy.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:

// proxy.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 Proxy

// 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>
  );
}

// proxy.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>

Proxy

// proxy.ts
import { auth0 } from "@/lib/auth0";
import type { NextRequest } from "next/server";

export async function proxy(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>
  );
}

Vercel-Native Identity Primitives

These are not replacements for Clerk, Descope, or Auth0. They cover cases where the identity comes from Vercel itself or where you need Vercel to hold the keys.

Sign in with Vercel

Let users log in with their Vercel account. Vercel's Identity Provider implements OAuth 2.0 and OpenID Connect: register an App in the dashboard, redirect to https://vercel.com/oauth/authorize with PKCE (code_challenge_method: 'S256'), state, and nonce, then exchange the code at https://api.vercel.com/login/oauth/token. Access tokens last 1 hour; refresh tokens last 30 days and rotate on use. Never hand-roll the token exchange without PKCE, state, and nonce checks. Docs: https://vercel.com/docs/sign-in-with-vercel/getting-started

Vercel Passport (deployment protection)

Passport protects whole deployments behind your own OIDC identity provider (Okta, Microsoft Entra ID, Auth0, or any OIDC-compatible provider). Vercel Connect stores the OAuth application configuration, and Vercel redirects unauthenticated visitors before any request reaches your code. Use it for internal tools and previews instead of application-level auth. Your app can read the verified visitor identity server-side or verify a forwarded Passport token as a JWT. Enterprise plan; GA since July 2026. Docs: https://vercel.com/docs/passport

Vercel KMS (managed signing keys)

KMS signs JWTs and messages with keys that never leave Vercel. Create an issuer in the team's Key Management settings, install @vercel/kms, and call signToken({ issuerId, claims, ttl }) inside a route handler or Server Component; the function's OIDC token authorizes the request automatically. Relying parties verify against the published JWKS at https://kms.vercel.com/<issuerId>/jwks.json. Use it instead of storing private signing keys in environment variables. Docs: https://vercel.com/docs/kms

Decision Matrix

Need	Recommended	Why
Fastest setup on Vercel	Clerk	Native Marketplace, auto-provisioned env vars
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
"Log in with Vercel" for a developer tool	Sign in with Vercel	Vercel is the identity provider
Restrict a deployment to employees behind Okta/Entra	Vercel Passport	Platform-level, no app code
Sign JWTs without storing private keys	Vercel KMS	Managed keys, OIDC-authorized signing

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+.

SignedIn/SignedOut/Protect replaced by Show — e.g. <Protect role="admin"> → <Show when={{ role: 'admin' }}>
Package renames — @clerk/clerk-react → @clerk/react, @clerk/clerk-expo → @clerk/expo
ClerkProvider must be inside <body>, not wrapping <html> — the CLI handles this automatically
@clerk/types removed — import types from the SDK's own /types entry point, or @clerk/shared/types for framework-agnostic code
Redirect props renamed — afterSignInUrl/afterSignUpUrl/redirectUrl → fallbackRedirectUrl/signUpFallbackRedirectUrl/forceRedirectUrl
Minimum Next.js version: 15.2.3 — Next.js 13 and 14 are no longer supported
Satellite domains — apps no longer auto-redirect on first visit; set satelliteAutoSync: true in middleware and ClerkProvider to restore Core 2 behavior
getToken() throws ClerkOfflineError when offline — previously returned null; still returns null when signed out

Cross-References

Marketplace install and env var provisioning → ⤳ skill: marketplace
Proxy and Routing Middleware patterns → ⤳ skill: routing-middleware
Accessing protected deployments from CLI or tests → ⤳ skill: access-protected-vercel-deployment
Environment variable management → ⤳ skill: env-vars

Official Documentation

Signals

GitHub stars: 290
Forks: 60
Last commit: Sep 2026

ahel review

K1binfo
installs-packages

Automated review, not a security audit. Ruleset v1+k2.

Advanced

Item type: skill
Key: auth-vercel
Source: github.com/vercel/vercel-plugin

github.com/vercel/vercel-plugin

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