clerk-install-auth

Install and configure Clerk SDK/CLI authentication. Use when setting up a new Clerk integration, configuring API keys, or initializing Clerk in your project. Trigger with phrases like "install clerk", "setup clerk", "clerk auth", "configure clerk API key", "add clerk to project".

Quality

77%

Does it follow best practices?

Impact

Pending

No eval scenarios have been run

Securityby

Passed

No known issues

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Clerk Install & Auth

Overview

Set up Clerk SDK and configure authentication for Next.js, React, or Express. This skill covers SDK installation, environment variables, ClerkProvider, middleware, and initial auth verification.

Prerequisites

Node.js 18+
Package manager (npm, pnpm, or yarn)
Clerk account at dashboard.clerk.com
Publishable Key (pk_test_*) and Secret Key (sk_test_*) from Clerk Dashboard > API Keys

Instructions

Step 1: Install SDK for Your Framework

set -euo pipefail
# Next.js (App Router or Pages Router)
npm install @clerk/nextjs

# React SPA (Vite, CRA, etc.)
npm install @clerk/clerk-react

# Express / Node.js backend
npm install @clerk/express

# Backend-only (Cloudflare Workers, serverless, etc.)
npm install @clerk/backend

Step 2: Configure Environment Variables

# .env.local — never commit this file
NEXT_PUBLIC_CLERK_PUBLISHABLE_KEY=pk_test_...
CLERK_SECRET_KEY=sk_test_...

# Optional: routing URLs
NEXT_PUBLIC_CLERK_SIGN_IN_URL=/sign-in
NEXT_PUBLIC_CLERK_SIGN_UP_URL=/sign-up
NEXT_PUBLIC_CLERK_AFTER_SIGN_IN_URL=/dashboard
NEXT_PUBLIC_CLERK_AFTER_SIGN_UP_URL=/onboarding

Ensure .env.local is in .gitignore:

echo ".env.local" >> .gitignore

Step 3: Add ClerkProvider (Next.js App Router)

// app/layout.tsx
import { ClerkProvider, SignInButton, SignedIn, SignedOut, UserButton } from '@clerk/nextjs'
import './globals.css'

export default function RootLayout({ children }: { children: React.ReactNode }) {
  return (
    <ClerkProvider>
      <html lang="en">
        <body>
          <header className="flex justify-between p-4">
            <SignedOut>
              <SignInButton />
            </SignedOut>
            <SignedIn>
              <UserButton />
            </SignedIn>
          </header>
          {children}
        </body>
      </html>
    </ClerkProvider>
  )
}

Step 4: Add Middleware

// middleware.ts (project root, NOT inside app/ or src/app/)
import { clerkMiddleware, createRouteMatcher } from '@clerk/nextjs/server'

// Define which routes should be publicly accessible
const isPublicRoute = createRouteMatcher([
  '/',
  '/sign-in(.*)',
  '/sign-up(.*)',
  '/api/webhooks(.*)',
])

export default clerkMiddleware(async (auth, req) => {
  if (!isPublicRoute(req)) {
    await auth.protect()
  }
})

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)(.*)',
  ],
}

Step 5: Create Sign-In and Sign-Up Pages

// app/sign-in/[[...sign-in]]/page.tsx
import { SignIn } from '@clerk/nextjs'

export default function SignInPage() {
  return (
    <div className="flex min-h-screen items-center justify-center">
      <SignIn />
    </div>
  )
}

// app/sign-up/[[...sign-up]]/page.tsx
import { SignUp } from '@clerk/nextjs'

export default function SignUpPage() {
  return (
    <div className="flex min-h-screen items-center justify-center">
      <SignUp />
    </div>
  )
}

Step 6: Verify Connection

// app/api/health/route.ts
import { auth } from '@clerk/nextjs/server'

export async function GET() {
  const { userId } = await auth()
  return Response.json({
    clerkConnected: true,
    authenticated: !!userId,
    userId: userId || null,
  })
}

React SPA Setup (Vite)

// src/main.tsx
import { ClerkProvider } from '@clerk/clerk-react'
import App from './App'

const PUBLISHABLE_KEY = import.meta.env.VITE_CLERK_PUBLISHABLE_KEY

if (!PUBLISHABLE_KEY) {
  throw new Error('Missing VITE_CLERK_PUBLISHABLE_KEY in .env')
}

ReactDOM.createRoot(document.getElementById('root')!).render(
  <ClerkProvider publishableKey={PUBLISHABLE_KEY}>
    <App />
  </ClerkProvider>
)

Express Setup

// server.ts
import express from 'express'
import { clerkMiddleware, requireAuth, getAuth } from '@clerk/express'

const app = express()

// Apply Clerk middleware globally — attaches auth to all requests
app.use(clerkMiddleware())

// Public route
app.get('/api/health', (req, res) => {
  res.json({ status: 'ok' })
})

// Protected route — redirects unauthenticated requests
app.get('/api/profile', requireAuth(), (req, res) => {
  const { userId } = getAuth(req)
  res.json({ userId })
})

app.listen(3001, () => console.log('Server running on :3001'))

Error Handling

Error	Cause	Solution
`Missing publishableKey`	Env var not set	Add `NEXT_PUBLIC_CLERK_PUBLISHABLE_KEY` to `.env.local`
`ClerkProvider must wrap your application`	Hook used outside provider	Ensure `ClerkProvider` wraps root layout
`auth() was called but Clerk can't detect clerkMiddleware()`	Middleware not running	Place `middleware.ts` at project root, check matcher
`Module not found: @clerk/nextjs`	Package not installed	Run `npm install @clerk/nextjs`
500 error on all pages	`CLERK_SECRET_KEY` missing or wrong	Verify key prefix matches environment (`sk_test_` for dev)

Enterprise Considerations

Use separate Clerk instances per environment (dev/staging/prod)
Store keys in platform secrets (Vercel, AWS Secrets Manager), never in .env files committed to git
The CLERK_SECRET_KEY must never be exposed client-side; only NEXT_PUBLIC_CLERK_PUBLISHABLE_KEY is safe for browsers
For monorepos, install @clerk/nextjs only in the app that needs it; use @clerk/backend for shared server packages
Enable Clerk's "Enhanced email deliverability" in production for reliable transactional emails

Resources

Next Steps

Proceed to clerk-hello-world for your first authenticated request.

Repository: jeremylongshore/claude-code-plugins-plus-skills
Commit: c8a915c

Last updated: 5 days ago
Created: 5 days ago

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