next.js/docs/02-app/02-api-reference/04-functions/headers.mdx

---
title: headers
description: API reference for the headers function.
---

The `headers` function allows you to read the HTTP incoming request headers from a [Server Component](/docs/app/building-your-application/rendering/server-components).

## `headers()`

This API extends the [Web Headers API](https://developer.mozilla.org/docs/Web/API/Headers). It is **read-only**, meaning you cannot `set` / `delete` the outgoing request headers.

```tsx filename="app/page.tsx" switcher
import { headers } from 'next/headers'

export default function Page() {
  const headersList = headers()
  const referer = headersList.get('referer')

  return <div>Referer: {referer}</div>
}
```

```jsx filename="app/page.js" switcher
import { headers } from 'next/headers'

export default function Page() {
  const headersList = headers()
  const referer = headersList.get('referer')

  return <div>Referer: {referer}</div>
}
```

> **Good to know**:
>
> - `headers()` is a **[Dynamic Function](/docs/app/building-your-application/rendering/server-components#server-rendering-strategies#dynamic-functions)** whose returned values cannot be known ahead of time. Using it in a layout or page will opt a route into **[dynamic rendering](/docs/app/building-your-application/rendering/server-components#dynamic-rendering)** at request time.

### API Reference

```tsx
const headersList = headers()
```

#### Parameters

`headers` does not take any parameters.

#### Returns

`headers` returns a **read-only** [Web Headers](https://developer.mozilla.org/docs/Web/API/Headers) object.

- [`Headers.entries()`](https://developer.mozilla.org/docs/Web/API/Headers/entries): Returns an [`iterator`](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Iteration_protocols) allowing to go through all key/value pairs contained in this object.
- [`Headers.forEach()`](https://developer.mozilla.org/docs/Web/API/Headers/forEach): Executes a provided function once for each key/value pair in this `Headers` object.
- [`Headers.get()`](https://developer.mozilla.org/docs/Web/API/Headers/get): Returns a [`String`](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String) sequence of all the values of a header within a `Headers` object with a given name.
- [`Headers.has()`](https://developer.mozilla.org/docs/Web/API/Headers/has): Returns a boolean stating whether a `Headers` object contains a certain header.
- [`Headers.keys()`](https://developer.mozilla.org/docs/Web/API/Headers/keys): Returns an [`iterator`](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Iteration_protocols) allowing you to go through all keys of the key/value pairs contained in this object.
- [`Headers.values()`](https://developer.mozilla.org/docs/Web/API/Headers/values): Returns an [`iterator`](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Iteration_protocols) allowing you to go through all values of the key/value pairs contained in this object.

### Examples

#### Usage with Data Fetching

`headers()` can be used in combination with [Suspense for Data Fetching](/docs/app/building-your-application/data-fetching/fetching-caching-and-revalidating).

```jsx filename="app/page.js"
import { Suspense } from 'react'
import { headers } from 'next/headers'

async function User() {
  const authorization = headers().get('authorization')
  const res = await fetch('...', {
    headers: { authorization }, // Forward the authorization header
  })
  const user = await res.json()

  return <h1>{user.name}</h1>
}

export default function Page() {
  return (
    <Suspense fallback={null}>
      <User />
    </Suspense>
  )
}
```

#### IP Address

`headers()` can be used to get the IP address of the client.

```jsx filename="app/page.js"
import { Suspense } from 'react'
import { headers } from 'next/headers'

function IP() {
  const FALLBACK_IP_ADDRESS = '0.0.0.0'
  const forwardedFor = headers().get('x-forwarded-for')

  if (forwardedFor) {
    return forwardedFor.split(',')[0] ?? FALLBACK_IP_ADDRESS
  }

  return headers().get('x-real-ip') ?? FALLBACK_IP_ADDRESS
}

export default function Page() {
  return (
    <Suspense fallback={null}>
      <IP />
    </Suspense>
  )
}
```

In addition to `x-forwarded-for`, `headers()` can also read:

- `x-real-ip`
- `x-forwarded-host`
- `x-forwarded-port`
- `x-forwarded-proto`

## Version History

| Version   | Changes               |
| --------- | --------------------- |
| `v13.0.0` | `headers` introduced. |