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Read session and user data in your Next.js app with Clerk

Clerk provides a set of hooks and helpers that you can use to access the active session and user data in your Next.js application. Here are examples of how to use these helpers in both the client and server side to get you started.

Server side

App Router

auth() and currentUser() are App Router-specific helpers that you can use inside of your Route Handlers, Middleware, Server Components, and Server Actions.

The auth() helper will return the Auth object of the currently active user. Now that request data is available in the global scope through Next.js's headers() and cookies() methods, passing the request object to Clerk is no longer required.

The currentUser() helper will return the Backend API User(opens in a new tab) object of the currently active user. This is helpful if you want to render information, like their first and last name, directly from the server.

Under the hood, currentUser() uses the clerkClient wrapper to make a call to Clerk's Backend API. This does count towards the Backend API Request Rate Limit. This also uses fetch() so it is automatically deduped per request.

Any requests from a Client Component to a Route Handler will read the session from cookies and will not need the token sent as a Bearer token.

This example uses the new auth() helper to validate an authenticated user and the new currentUser() helper to access the Backend API User object for the authenticated user.

app/page.tsx
import { auth, currentUser } from "@clerk/nextjs"; export default async function Page() { // Get the userId from auth() -- if null, the user is not signed in const { userId } = auth(); if (userId) { // Query DB for user specific information or display assets only to signed in users } // Get the Backend API User object when you need access to the user's information const user = await currentUser() // Use `user` to render user details or create UI elements }

Pages Router

For Next.js applications using the Pages Router, you can retrieve information about the user and their authentication state, or control access to some or all of your API routes by using the getAuth() helper. The getAuth() helper does require Middleware.

pages/api/auth.ts
import type { NextApiRequest, NextApiResponse } from "next"; import { getAuth } from "@clerk/nextjs/server"; export default function handler(req: NextApiRequest, res: NextApiResponse) { const { userId } = getAuth(req); if (!userId) { return res.status(401).json({ error: "Unauthorized" }); } // retrieve data from your database res.status(200).json({}); }

Client side

useAuth

The useAuth hook is a convenient way to access the current auth state. This hook provides the minimal information needed for data-loading and helper methods to manage the current active session.

example.tsx
"use client"; import { useAuth } from "@clerk/nextjs"; export default function Example() { const { isLoaded, userId, sessionId, getToken } = useAuth(); // In case the user signs out while on the page. if (!isLoaded || !userId) { return null; } return ( <div> Hello, {userId} your current active session is {sessionId} </div> ); }

useUser

The useUser hook is a convenient way to access the current user data where you need it. This hook provides the user data and helper methods to manage the current active session.

example.tsx
"use client"; import { useUser } from "@clerk/nextjs"; export default function Example() { const { isLoaded, isSignedIn, user } = useUser(); if (!isLoaded || !isSignedIn) { return null; } return <div>Hello, {user.firstName} welcome to Clerk</div>; }

Last updated on March 8, 2024

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