---

name: clerk-hello-world description: | Create your first authenticated request with Clerk. Use when making initial API calls, testing authentication, or verifying Clerk integration works correctly. Trigger with phrases like "clerk hello world", "first clerk request", "test clerk auth", "verify clerk setup". allowed-tools: Read, Write, Edit, Bash(npm:*), Grep version: 1.0.0 license: MIT author: Jeremy Longshore jeremy@intentsolutions.io

Clerk Hello World

Overview

Make your first authenticated request using Clerk to verify the integration works.

Prerequisites

• Clerk SDK installed (clerk-install-auth completed)
• Environment variables configured
• ClerkProvider wrapping application

Instructions

Step 1: Create Protected Page

// app/dashboard/page.tsx
import { auth, currentUser } from '@clerk/nextjs/server'

export default async function DashboardPage() {
  const { userId } = await auth()
  const user = await currentUser()

  if (!userId) {
    return <div>Please sign in to access this page</div>
  }

  return (
    <div>
      <h1>Hello, {user?.firstName || 'User'}!</h1>
      <p>Your user ID: {userId}</p>
      <p>Email: {user?.emailAddresses[0]?.emailAddress}</p>
    </div>
  )
}

Step 2: Create Protected API Route

// app/api/hello/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({
    message: 'Hello from Clerk!',
    userId,
    timestamp: new Date().toISOString()
  })
}

Step 3: Test Authentication Flow

// Client-side test component
'use client'
import { useUser, useAuth } from '@clerk/nextjs'

export function AuthTest() {
  const { user, isLoaded, isSignedIn } = useUser()
  const { getToken } = useAuth()

  if (!isLoaded) return <div>Loading...</div>
  if (!isSignedIn) return <div>Not signed in</div>

  const testAPI = async () => {
    const token = await getToken()
    const res = await fetch('/api/hello', {
      headers: { Authorization: `Bearer ${token}` }
    })
    console.log(await res.json())
  }

  return (
    <div>
      <p>Signed in as: {user.primaryEmailAddress?.emailAddress}</p>
      <button onClick={testAPI}>Test API</button>
    </div>
  )
}

Output

• Protected page showing user information
• API route returning authenticated user data
• Successful request/response verification

Error Handling

Error	Cause	Solution
userId is null	User not authenticated	Redirect to sign-in or check middleware
currentUser returns null	Session expired	Refresh page or re-authenticate
401 Unauthorized	Token missing or invalid	Check Authorization header
Hydration Error	Server/client mismatch	Use 'use client' for client hooks

Examples

Using with React Hooks

'use client'
import { useUser, useClerk } from '@clerk/nextjs'

export function UserProfile() {
  const { user } = useUser()
  const { signOut } = useClerk()

  return (
    <div>
      <img src={user?.imageUrl} alt="Profile" />
      <h2>{user?.fullName}</h2>
      <button onClick={() => signOut()}>Sign Out</button>
    </div>
  )
}

Express.js Example

import { clerkMiddleware, requireAuth } from '@clerk/express'

app.use(clerkMiddleware())

app.get('/api/protected', requireAuth(), (req, res) => {
  res.json({
    message: 'Hello!',
    userId: req.auth.userId
  })
})

Resources

• Clerk Auth Object
• Clerk Hooks
• Protected Routes

Next Steps

Proceed to clerk-local-dev-loop for local development workflow setup.