Clerk Install & Auth

Overview

Set up Clerk SDK and configure authentication credentials for your application.

Prerequisites

Node.js 18+ (Next.js, React, Express, etc.)
Package manager (npm, pnpm, or yarn)
Clerk account with API access
Publishable and Secret keys from Clerk dashboard

Instructions

Step 1: Install SDK

# Next.js
npm install @clerk/nextjs

# React
npm install @clerk/clerk-react

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

# Remix
npm install @clerk/remix

Step 2: Configure Environment Variables

# Create .env.local file
cat >> .env.local << 'EOF'
NEXT_PUBLIC_CLERK_PUBLISHABLE_KEY=pk_test_...
CLERK_SECRET_KEY=sk_test_...
EOF

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

// 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>
  )
}

Step 4: Add Middleware

// middleware.ts
import { clerkMiddleware } from '@clerk/nextjs/server'

export default clerkMiddleware()

export const config = {
  matcher: [
    '/((?!_next|[^?]*\\.(?:html?|css|js(?!on)|jpe?g|webp|png|gif|svg|ttf|woff2?|ico|csv|docx?|xlsx?|zip|webmanifest)).*)',
    '/(api|trpc)(.*)',
  ],
}

Step 5: Verify Connection

import { auth } from '@clerk/nextjs/server'

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

Output

Installed SDK package in node_modules
Environment variables configured in .env.local
ClerkProvider wrapping application
Middleware protecting routes

Error Handling

| Error | Cause | Solution | |-------|-------|----------| | Invalid API Key | Incorrect or mismatched keys | Verify keys in Clerk dashboard match environment | | ClerkProvider Missing | SDK used outside provider | Wrap app root with ClerkProvider | | Middleware Not Running | Matcher misconfigured | Check matcher regex in middleware.ts | | Module Not Found | Installation failed | Run npm install @clerk/nextjs again |

Examples

Next.js App Router Setup

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

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

React SPA Setup

import { ClerkProvider } from '@clerk/clerk-react'

const PUBLISHABLE_KEY = import.meta.env.VITE_CLERK_PUBLISHABLE_KEY

function App() {
  return (
    <ClerkProvider publishableKey={PUBLISHABLE_KEY}>
      <Router />
    </ClerkProvider>
  )
}

Resources

Next Steps

After successful auth, proceed to clerk-hello-world for your first authenticated request.