Clerk SDK Patterns

Overview

Common patterns and best practices for using the Clerk SDK effectively across server components, client components, API routes, and middleware.

Prerequisites

• Clerk SDK installed and configured
• Basic understanding of React/Next.js
• ClerkProvider wrapping application

Instructions

Pattern 1: Server-Side Authentication

// Server Component — use auth() for lightweight checks
import { auth } from '@clerk/nextjs/server'

export default async function ServerPage() {
  const { userId, orgId, has } = await auth()

  if (!userId) return <div>Not authenticated</div>
  if (!has({ permission: 'org:posts:create' })) return <div>No permission</div>

  return <div>Authorized content for {userId}</div>
}

// Use currentUser() when you need full user profile data
import { currentUser } from '@clerk/nextjs/server'

export default async function ProfilePage() {
  const user = await currentUser()
  if (!user) return null

  return (
    <div>
      <h1>{user.firstName} {user.lastName}</h1>
      <p>{user.emailAddresses[0]?.emailAddress}</p>
      <img src={user.imageUrl} alt="Avatar" />
    </div>
  )
}

Pattern 2: Client-Side Hooks

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

export function ClientAuthExample() {
  const { user, isLoaded, isSignedIn } = useUser()       // Full user object
  const { userId, getToken, signOut } = useAuth()          // Auth state + token access
  const { openSignIn, openUserProfile } = useClerk()       // UI controls

  if (!isLoaded) return <div>Loading...</div>
  if (!isSignedIn) return <button onClick={() => openSignIn()}>Sign In</button>

  const fetchWithAuth = async (url: string) => {
    const token = await getToken()
    return fetch(url, {
      headers: { Authorization: `Bearer ${token}` },
    })
  }

  return (
    <div>
      <p>Hello, {user.firstName}</p>
      <button onClick={() => openUserProfile()}>Profile</button>
      <button onClick={() => signOut()}>Sign Out</button>
    </div>
  )
}