next.js/docs/01-app/03-api-reference/05-config/01-next-config-js/headers.mdx

---
title: headers
description: Add custom HTTP headers to your Next.js app.
---

{/* The content of this doc is shared between the app and pages router. You can use the `<PagesOnly>Content</PagesOnly>` component to add content that is specific to the Pages Router. Any shared content should not be wrapped in a component. */}

Headers allow you to set custom HTTP headers on the response to an incoming request on a given path.

To set custom HTTP headers you can use the `headers` key in `next.config.js`:

```js filename="next.config.js"
module.exports = {
  async headers() {
    return [
      {
        source: '/about',
        headers: [
          {
            key: 'x-custom-header',
            value: 'my custom header value',
          },
          {
            key: 'x-another-custom-header',
            value: 'my other custom header value',
          },
        ],
      },
    ]
  },
}
```

`headers` is an async function that expects an array to be returned holding objects with `source` and `headers` properties:

- `source` is the incoming request path pattern.
- `headers` is an array of response header objects, with `key` and `value` properties.
- `basePath`: `false` or `undefined` - if false the basePath won't be included when matching, can be used for external rewrites only.
- `locale`: `false` or `undefined` - whether the locale should not be included when matching.
- `has` is an array of [has objects](#header-cookie-and-query-matching) with the `type`, `key` and `value` properties.
- `missing` is an array of [missing objects](#header-cookie-and-query-matching) with the `type`, `key` and `value` properties.

Headers are checked before the filesystem which includes pages and `/public` files.

## Header Overriding Behavior

If two headers match the same path and set the same header key, the last header key will override the first. Using the below headers, the path `/hello` will result in the header `x-hello` being `world` due to the last header value set being `world`.

```js filename="next.config.js"
module.exports = {
  async headers() {
    return [
      {
        source: '/:path*',
        headers: [
          {
            key: 'x-hello',
            value: 'there',
          },
        ],
      },
      {
        source: '/hello',
        headers: [
          {
            key: 'x-hello',
            value: 'world',
          },
        ],
      },
    ]
  },
}
```

## Path Matching

Path matches are allowed, for example `/blog/:slug` will match `/blog/hello-world` (no nested paths):

```js filename="next.config.js"
module.exports = {
  async headers() {
    return [
      {
        source: '/blog/:slug',
        headers: [
          {
            key: 'x-slug',
            value: ':slug', // Matched parameters can be used in the value
          },
          {
            key: 'x-slug-:slug', // Matched parameters can be used in the key
            value: 'my other custom header value',
          },
        ],
      },
    ]
  },
}
```

### Wildcard Path Matching

To match a wildcard path you can use `*` after a parameter, for example `/blog/:slug*` will match `/blog/a/b/c/d/hello-world`:

```js filename="next.config.js"
module.exports = {
  async headers() {
    return [
      {
        source: '/blog/:slug*',
        headers: [
          {
            key: 'x-slug',
            value: ':slug*', // Matched parameters can be used in the value
          },
          {
            key: 'x-slug-:slug*', // Matched parameters can be used in the key
            value: 'my other custom header value',
          },
        ],
      },
    ]
  },
}
```

### Regex Path Matching

To match a regex path you can wrap the regex in parenthesis after a parameter, for example `/blog/:slug(\\d{1,})` will match `/blog/123` but not `/blog/abc`:

```js filename="next.config.js"
module.exports = {
  async headers() {
    return [
      {
        source: '/blog/:post(\\d{1,})',
        headers: [
          {
            key: 'x-post',
            value: ':post',
          },
        ],
      },
    ]
  },
}
```

The following characters `(`, `)`, `{`, `}`, `:`, `*`, `+`, `?` are used for regex path matching, so when used in the `source` as non-special values they must be escaped by adding `\\` before them:

```js filename="next.config.js"
module.exports = {
  async headers() {
    return [
      {
        // this will match `/english(default)/something` being requested
        source: '/english\\(default\\)/:slug',
        headers: [
          {
            key: 'x-header',
            value: 'value',
          },
        ],
      },
    ]
  },
}
```

## Header, Cookie, and Query Matching

To only apply a header when header, cookie, or query values also match the `has` field or don't match the `missing` field can be used. Both the `source` and all `has` items must match and all `missing` items must not match for the header to be applied.

`has` and `missing` items can have the following fields:

- `type`: `String` - must be either `header`, `cookie`, `host`, or `query`.
- `key`: `String` - the key from the selected type to match against.
- `value`: `String` or `undefined` - the value to check for, if undefined any value will match. A regex like string can be used to capture a specific part of the value, e.g. if the value `first-(?<paramName>.*)` is used for `first-second` then `second` will be usable in the destination with `:paramName`.

```js filename="next.config.js"
module.exports = {
  async headers() {
    return [
      // if the header `x-add-header` is present,
      // the `x-another-header` header will be applied
      {
        source: '/:path*',
        has: [
          {
            type: 'header',
            key: 'x-add-header',
          },
        ],
        headers: [
          {
            key: 'x-another-header',
            value: 'hello',
          },
        ],
      },
      // if the header `x-no-header` is not present,
      // the `x-another-header` header will be applied
      {
        source: '/:path*',
        missing: [
          {
            type: 'header',
            key: 'x-no-header',
          },
        ],
        headers: [
          {
            key: 'x-another-header',
            value: 'hello',
          },
        ],
      },
      // if the source, query, and cookie are matched,
      // the `x-authorized` header will be applied
      {
        source: '/specific/:path*',
        has: [
          {
            type: 'query',
            key: 'page',
            // the page value will not be available in the
            // header key/values since value is provided and
            // doesn't use a named capture group e.g. (?<page>home)
            value: 'home',
          },
          {
            type: 'cookie',
            key: 'authorized',
            value: 'true',
          },
        ],
        headers: [
          {
            key: 'x-authorized',
            value: ':authorized',
          },
        ],
      },
      // if the header `x-authorized` is present and
      // contains a matching value, the `x-another-header` will be applied
      {
        source: '/:path*',
        has: [
          {
            type: 'header',
            key: 'x-authorized',
            value: '(?<authorized>yes|true)',
          },
        ],
        headers: [
          {
            key: 'x-another-header',
            value: ':authorized',
          },
        ],
      },
      // if the host is `example.com`,
      // this header will be applied
      {
        source: '/:path*',
        has: [
          {
            type: 'host',
            value: 'example.com',
          },
        ],
        headers: [
          {
            key: 'x-another-header',
            value: ':authorized',
          },
        ],
      },
    ]
  },
}
```

## Headers with basePath support

When leveraging [`basePath` support](/docs/app/api-reference/config/next-config-js/basePath) with headers each `source` is automatically prefixed with the `basePath` unless you add `basePath: false` to the header:

```js filename="next.config.js"
module.exports = {
  basePath: '/docs',

  async headers() {
    return [
      {
        source: '/with-basePath', // becomes /docs/with-basePath
        headers: [
          {
            key: 'x-hello',
            value: 'world',
          },
        ],
      },
      {
        source: '/without-basePath', // is not modified since basePath: false is set
        headers: [
          {
            key: 'x-hello',
            value: 'world',
          },
        ],
        basePath: false,
      },
    ]
  },
}
```

## Headers with i18n support

<AppOnly>

When leveraging [`i18n` support](/docs/app/guides/internationalization) with headers each `source` is automatically prefixed to handle the configured `locales` unless you add `locale: false` to the header. If `locale: false` is used you must prefix the `source` with a locale for it to be matched correctly.

</AppOnly>

<PagesOnly>

When leveraging [`i18n` support](/docs/pages/guides/internationalization) with headers each `source` is automatically prefixed to handle the configured `locales` unless you add `locale: false` to the header. If `locale: false` is used you must prefix the `source` with a locale for it to be matched correctly.

</PagesOnly>

```js filename="next.config.js"
module.exports = {
  i18n: {
    locales: ['en', 'fr', 'de'],
    defaultLocale: 'en',
  },

  async headers() {
    return [
      {
        source: '/with-locale', // automatically handles all locales
        headers: [
          {
            key: 'x-hello',
            value: 'world',
          },
        ],
      },
      {
        // does not handle locales automatically since locale: false is set
        source: '/nl/with-locale-manual',
        locale: false,
        headers: [
          {
            key: 'x-hello',
            value: 'world',
          },
        ],
      },
      {
        // this matches '/' since `en` is the defaultLocale
        source: '/en',
        locale: false,
        headers: [
          {
            key: 'x-hello',
            value: 'world',
          },
        ],
      },
      {
        // this gets converted to /(en|fr|de)/(.*) so will not match the top-level
        // `/` or `/fr` routes like /:path* would
        source: '/(.*)',
        headers: [
          {
            key: 'x-hello',
            value: 'world',
          },
        ],
      },
    ]
  },
}
```

## Cache-Control

Next.js sets the `Cache-Control` header of `public, max-age=31536000, immutable` for truly immutable assets. It cannot be overridden. These immutable files contain a SHA-hash in the file name, so they can be safely cached indefinitely. For example, [Static Image Imports](/docs/app/getting-started/images#local-images). You cannot set `Cache-Control` headers in `next.config.js` for these assets.

However, you can set `Cache-Control` headers for other responses or data.

<AppOnly>

Learn more about [caching](/docs/app/guides/caching) with the App Router.

</AppOnly>

<PagesOnly>

If you need to revalidate the cache of a page that has been [statically generated](/docs/pages/building-your-application/rendering/static-site-generation), you can do so by setting the `revalidate` prop in the page's [`getStaticProps`](/docs/pages/building-your-application/data-fetching/get-static-props) function.

To cache the response from an [API Route](/docs/pages/building-your-application/routing/api-routes), you can use `res.setHeader`:

```ts filename="pages/api/hello.ts" switcher
import type { NextApiRequest, NextApiResponse } from 'next'

type ResponseData = {
  message: string
}

export default function handler(
  req: NextApiRequest,
  res: NextApiResponse<ResponseData>
) {
  res.setHeader('Cache-Control', 's-maxage=86400')
  res.status(200).json({ message: 'Hello from Next.js!' })
}
```

```js filename="pages/api/hello.js" switcher
export default function handler(req, res) {
  res.setHeader('Cache-Control', 's-maxage=86400')
  res.status(200).json({ message: 'Hello from Next.js!' })
}
```

You can also use caching headers (`Cache-Control`) inside `getServerSideProps` to cache dynamic responses. For example, using [`stale-while-revalidate`](https://web.dev/stale-while-revalidate/).

```ts filename="pages/index.tsx" switcher
import { GetStaticProps, GetStaticPaths, GetServerSideProps } from 'next'

// This value is considered fresh for ten seconds (s-maxage=10).
// If a request is repeated within the next 10 seconds, the previously
// cached value will still be fresh. If the request is repeated before 59 seconds,
// the cached value will be stale but still render (stale-while-revalidate=59).
//
// In the background, a revalidation request will be made to populate the cache
// with a fresh value. If you refresh the page, you will see the new value.
export const getServerSideProps = (async (context) => {
  context.res.setHeader(
    'Cache-Control',
    'public, s-maxage=10, stale-while-revalidate=59'
  )

  return {
    props: {},
  }
}) satisfies GetServerSideProps
```

```js filename="pages/index.js" switcher
// This value is considered fresh for ten seconds (s-maxage=10).
// If a request is repeated within the next 10 seconds, the previously
// cached value will still be fresh. If the request is repeated before 59 seconds,
// the cached value will be stale but still render (stale-while-revalidate=59).
//
// In the background, a revalidation request will be made to populate the cache
// with a fresh value. If you refresh the page, you will see the new value.
export async function getServerSideProps({ req, res }) {
  res.setHeader(
    'Cache-Control',
    'public, s-maxage=10, stale-while-revalidate=59'
  )

  return {
    props: {},
  }
}
```

</PagesOnly>

## Options

### CORS

[Cross-Origin Resource Sharing (CORS)](https://developer.mozilla.org/docs/Web/HTTP/CORS) is a security feature that allows you to control which sites can access your resources. You can set the `Access-Control-Allow-Origin` header to allow a specific origin to access your <PagesOnly>API Endpoints</PagesOnly><AppOnly>Route Handlers</AppOnly>.

```js
async headers() {
    return [
      {
        source: "/api/:path*",
        headers: [
          {
            key: "Access-Control-Allow-Origin",
            value: "*", // Set your origin
          },
          {
            key: "Access-Control-Allow-Methods",
            value: "GET, POST, PUT, DELETE, OPTIONS",
          },
          {
            key: "Access-Control-Allow-Headers",
            value: "Content-Type, Authorization",
          },
        ],
      },
    ];
  },
```

### X-DNS-Prefetch-Control

[This header](https://developer.mozilla.org/docs/Web/HTTP/Headers/X-DNS-Prefetch-Control) controls DNS prefetching, allowing browsers to proactively perform domain name resolution on external links, images, CSS, JavaScript, and more. This prefetching is performed in the background, so the [DNS](https://developer.mozilla.org/docs/Glossary/DNS) is more likely to be resolved by the time the referenced items are needed. This reduces latency when the user clicks a link.

```js
{
  key: 'X-DNS-Prefetch-Control',
  value: 'on'
}
```

### Strict-Transport-Security

[This header](https://developer.mozilla.org/docs/Web/HTTP/Headers/Strict-Transport-Security) informs browsers it should only be accessed using HTTPS, instead of using HTTP. Using the configuration below, all present and future subdomains will use HTTPS for a `max-age` of 2 years. This blocks access to pages or subdomains that can only be served over HTTP.

```js
{
  key: 'Strict-Transport-Security',
  value: 'max-age=63072000; includeSubDomains; preload'
}
```

### X-Frame-Options

[This header](https://developer.mozilla.org/docs/Web/HTTP/Headers/X-Frame-Options) indicates whether the site should be allowed to be displayed within an `iframe`. This can prevent against clickjacking attacks.

**This header has been superseded by CSP's `frame-ancestors` option**, which has better support in modern browsers (see [Content Security Policy](/docs/app/guides/content-security-policy) for configuration details).

```js
{
  key: 'X-Frame-Options',
  value: 'SAMEORIGIN'
}
```

### Permissions-Policy

[This header](https://developer.mozilla.org/docs/Web/HTTP/Headers/Permissions-Policy) allows you to control which features and APIs can be used in the browser. It was previously named `Feature-Policy`.

```js
{
  key: 'Permissions-Policy',
  value: 'camera=(), microphone=(), geolocation=(), browsing-topics=()'
}
```

### X-Content-Type-Options

[This header](https://developer.mozilla.org/docs/Web/HTTP/Headers/X-Content-Type-Options) prevents the browser from attempting to guess the type of content if the `Content-Type` header is not explicitly set. This can prevent XSS exploits for websites that allow users to upload and share files.

For example, a user trying to download an image, but having it treated as a different `Content-Type` like an executable, which could be malicious. This header also applies to downloading browser extensions. The only valid value for this header is `nosniff`.

```js
{
  key: 'X-Content-Type-Options',
  value: 'nosniff'
}
```

### Referrer-Policy

[This header](https://developer.mozilla.org/docs/Web/HTTP/Headers/Referrer-Policy) controls how much information the browser includes when navigating from the current website (origin) to another.

```js
{
  key: 'Referrer-Policy',
  value: 'origin-when-cross-origin'
}
```

### Content-Security-Policy

Learn more about adding a [Content Security Policy](/docs/app/guides/content-security-policy) to your application.

## Version History

| Version   | Changes          |
| --------- | ---------------- |
| `v13.3.0` | `missing` added. |
| `v10.2.0` | `has` added.     |
| `v9.5.0`  | Headers added.   |