Headers

The headers function allows you to read the HTTP incoming request headers from a server component.

headers()

This API extends the Web Headers API. It is read-only, meaning you cannot set / delete the outgoing request headers.

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 whose returned values cannot be known ahead of time. Using it in a layout or page will opt a route into dynamic rendering at request time.

API Reference

const headersList = headers();

Parameters

headers does not take any parameters.

Returns

headers returns a read-only Web Headers object.

• Headers.entries(): Returns an iterator allowing to go through all key/value pairs contained in this object.
• Headers.forEach(): Executes a provided function once for each key/value pair in this Headers object.
• Headers.get(): Returns a String sequence of all the values of a header within a Headers object with a given name.
• Headers.has(): Returns a boolean stating whether a Headers object contains a certain header.
• Headers.keys(): Returns an iterator allowing you to go through all keys of the key/value pairs contained in this object.
• Headers.values(): Returns an iterator 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.

import { headers } from 'next/headers';

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

export default async function UserPage() {
  const user = await getUser()
  return <h1>{user.name}</h1>
}