vercel__next.js/errors/react-client-hook-in-server-component.mdx

---
title: React client hook in Server Component
---

## Why This Error Occurred

You are using a React client hook in a Server Component.

## Possible Ways to Fix It

Mark the component using the hook as a Client Component by adding `'use client'` at the top of the file.

### Before

```jsx filename="app/example.js"
import { useEffect } from 'react'

export default function Example() {
  useEffect(() => {
    console.log('in useEffect')
  })
  return <p>Hello world</p>
}
```

### After

```jsx filename="app/example.js"
'use client'

import { useEffect } from 'react'

export default function Example() {
  useEffect(() => {
    console.log('in useEffect')
  })
  return <p>Hello world</p>
}
```

## Useful Links

- [Server Components](/docs/app/getting-started/server-and-client-components)