# buildClerkProps

The `buildClerkProps()` function is used in your Next.js application's `getServerSideProps` to pass authentication state from the server to the client. It returns props that get spread into the `<ClerkProvider>` component. This enables Clerk's client-side helpers, such as `useAuth()`, to correctly determine the user's authentication status during server-side rendering.

filename: pages/example.tsx
```tsx
import { getAuth, buildClerkProps } from '@clerk/nextjs/server'
import { GetServerSideProps } from 'next'

export const getServerSideProps: GetServerSideProps = async (ctx) => {
  // Use `getAuth()` to access `isAuthenticated` and the user's ID
  const { isAuthenticated, userId } = getAuth(ctx.req)

  // Protect the route by checking if the user is signed in
  if (!isAuthenticated) {
    return {
      redirect: {
        destination: '/sign-in',
        permanent: false,
      },
    }
  }

  // Initialize `clerkClient`
  const client = await clerkClient()

  // Use the `getUser()` method to get the user's full `Backend User` object
  const user = await client.users.getUser(userId)

  // Pass the `user` object to buildClerkProps()
  return { props: { ...buildClerkProps(ctx.req, { user }) } }
}
```

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