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API ReferenceFunctionsgenerateMetadata

generateMetadata

You can use the metadata object or the generateMetadata function to define metadata.

The metadata object

To define static metadata, export a Metadata object from a layout.js or page.js file.

layout.tsx | page.tsx
import type { Metadata } from 'next'
 
export const metadata: Metadata = {
  title: '...',
  description: '...',
}
 
export default function Page() {}

See the Metadata Fields for a complete list of supported options.

generateMetadata function

Dynamic metadata depends on dynamic information, such as the current route parameters, external data, or metadata in parent segments, can be set by exporting a generateMetadata function that returns a Metadata object.

app/products/[id]/page.tsx
import type { Metadata, ResolvingMetadata } from 'next'
 
type Props = {
  params: Promise<{ id: string }>
  searchParams: Promise<{ [key: string]: string | string[] | undefined }>
}
 
export async function generateMetadata(
  { params, searchParams }: Props,
  parent: ResolvingMetadata
): Promise<Metadata> {
  // read route params
  const { id } = await params
 
  // fetch data
  const product = await fetch(`https://.../${id}`).then((res) => res.json())
 
  // optionally access and extend (rather than replace) parent metadata
  const previousImages = (await parent).openGraph?.images || []
 
  return {
    title: product.title,
    openGraph: {
      images: ['/some-specific-page-image.jpg', ...previousImages],
    },
  }
}
 
export default function Page({ params, searchParams }: Props) {}

Good to know:

  • Metadata can be added to layout.js and page.js files.
  • Next.js will automatically resolve the metadata, and create the relevant <head> tags for the page.
  • The metadata object and generateMetadata function exports are only supported in Server Components.
  • You cannot export both the metadata object and generateMetadata function from the same route segment.
  • fetch requests inside generateMetadata are automatically memoized for the same data across generateMetadata, generateStaticParams, Layouts, Pages, and Server Components.
  • React cache can be used if fetch is unavailable. - File-based metadat has the higher priority and will override the metadata object and generateMetadata function.

Reference

Parameters

generateMetadata function accepts the following parameters:

  • props - An object containing the parameters of the current route:

    • params - An object containing the dynamic route parameters object from the root segment down to the segment generateMetadata is called from. Examples:

      RouteURLparams
      app/shop/[slug]/page.js/shop/1{ slug: '1' }
      app/shop/[tag]/[item]/page.js/shop/1/2{ tag: '1', item: '2' }
      app/shop/[...slug]/page.js/shop/1/2{ slug: ['1', '2'] }

    • searchParams - An object containing the current URL's search params. Examples:

      URLsearchParams
      /shop?a=1{ a: '1' }
      /shop?a=1&b=2{ a: '1', b: '2' }
      /shop?a=1&a=2{ a: ['1', '2'] }

  • parent - A promise of the resolved metadata from parent route segments.

Returns

generateMetadata should return a Metadata object containing one or more metadata fields.

Good to know:

  • If metadata doesn't depend on runtime information, it should be defined using the static metadata object rather than generateMetadata.
  • fetch requests are automatically memoized for the same data across generateMetadata, generateStaticParams, Layouts, Pages, and Server Components. React cache can be used if fetch is unavailable.
  • searchParams are only available in page.js segments.
  • The redirect() and notFound() Next.js methods can also be used inside generateMetadata.

Metadata Fields

The following fields are supported:

title

The title attribute is used to set the title of the document. It can be defined as a simple string or an optional template object.

String
layout.js | page.js
export const metadata = {
  title: 'Next.js',
}
<head> output
<title>Next.js</title>
default

title.default can be used to provide a fallback title to child route segments that don't define a title.

app/layout.tsx
import type { Metadata } from 'next'
 
export const metadata: Metadata = {
  title: {
    default: 'Acme',
  },
}
app/about/page.tsx
import type { Metadata } from 'next'
 
export const metadata: Metadata = {}
 
// Output: <title>Acme</title>
template

title.template can be used to add a prefix or a suffix to titles defined in child route segments.

app/layout.tsx
import type { Metadata } from 'next'
 
export const metadata: Metadata = {
  title: {
    template: '%s | Acme',
    default: 'Acme', // a default is required when creating a template
  },
}
app/about/page.tsx
import type { Metadata } from 'next'
 
export const metadata: Metadata = {
  title: 'About',
}
 
// Output: <title>About | Acme</title>

Good to know:

  • title.template applies to child route segments and not the segment it's defined in. This means:

    • title.default is required when you add a title.template.
    • title.template defined in layout.js will not apply to a title defined in a page.js of the same route segment.
    • title.template defined in page.js has no effect because a page is always the terminating segment (it doesn't have any children route segments).

  • title.template has no effect if a route has not defined a title or title.default.

absolute

title.absolute can be used to provide a title that ignores title.template set in parent segments.

app/layout.tsx
import type { Metadata } from 'next'
 
export const metadata: Metadata = {
  title: {
    template: '%s | Acme',
  },
}
app/about/page.tsx
import type { Metadata } from 'next'
 
export const metadata: Metadata = {
  title: {
    absolute: 'About',
  },
}
 
// Output: <title>About</title>

Good to know:

  • layout.js

    • title (string) and title.default define the default title for child segments (that do not define their own title). It will augment title.template from the closest parent segment if it exists.
    • title.absolute defines the default title for child segments. It ignores title.template from parent segments.
    • title.template defines a new title template for child segments.

  • page.js

    • If a page does not define its own title the closest parents resolved title will be used.
    • title (string) defines the routes title. It will augment title.template from the closest parent segment if it exists.
    • title.absolute defines the route title. It ignores title.template from parent segments.
    • title.template has no effect in page.js because a page is always the terminating segment of a route.

description

layout.js | page.js
export const metadata = {
  description: 'The React Framework for the Web',
}
<head> output
<meta name="description" content="The React Framework for the Web" />

Other fields

layout.js | page.js
export const metadata = {
  generator: 'Next.js',
  applicationName: 'Next.js',
  referrer: 'origin-when-cross-origin',
  keywords: ['Next.js', 'React', 'JavaScript'],
  authors: [{ name: 'Seb' }, { name: 'Josh', url: 'https://nextjs.org' }],
  creator: 'Jiachi Liu',
  publisher: 'Sebastian Markbåge',
  formatDetection: {
    email: false,
    address: false,
    telephone: false,
  },
}
<head> output
<meta name="application-name" content="Next.js" />
<meta name="author" content="Seb" />
<link rel="author" href="https://nextjs.org" />
<meta name="author" content="Josh" />
<meta name="generator" content="Next.js" />
<meta name="keywords" content="Next.js,React,JavaScript" />
<meta name="referrer" content="origin-when-cross-origin" />
<meta name="color-scheme" content="dark" />
<meta name="creator" content="Jiachi Liu" />
<meta name="publisher" content="Sebastian Markbåge" />
<meta name="format-detection" content="telephone=no, address=no, email=no" />

metadataBase

metadataBase is a convenience option to set a base URL prefix for metadata fields that require a fully qualified URL.

  • metadataBase allows URL-based metadata fields defined in the current route segment and below to use a relative path instead of an otherwise required absolute URL.
  • The field's relative path will be composed with metadataBase to form a fully qualified URL.
layout.js | page.js
export const metadata = {
  metadataBase: new URL('https://acme.com'),
  alternates: {
    canonical: '/',
    languages: {
      'en-US': '/en-US',
      'de-DE': '/de-DE',
    },
  },
  openGraph: {
    images: '/og-image.png',
  },
}
<head> output
<link rel="canonical" href="https://acme.com" />
<link rel="alternate" hreflang="en-US" href="https://acme.com/en-US" />
<link rel="alternate" hreflang="de-DE" href="https://acme.com/de-DE" />
<meta property="og:image" content="https://acme.com/og-image.png" />

Good to know:

  • metadataBase is typically set in root app/layout.js to apply to URL-based metadata fields across all routes.
  • All URL-based metadata fields that require absolute URLs can be configured with a metadataBase option.
  • metadataBase can contain a subdomain e.g. https://app.acme.com or base path e.g. https://acme.com/start/from/here
  • If a metadata field provides an absolute URL, metadataBase will be ignored.
  • Using a relative path in a URL-based metadata field without configuring a metadataBase will cause a build error.
  • Next.js will normalize duplicate slashes between metadataBase (e.g. https://acme.com/) and a relative field (e.g. /path) to a single slash (e.g. https://acme.com/path)

URL Composition

URL composition favors developer intent over default directory traversal semantics.

  • Trailing slashes between metadataBase and metadata fields are normalized.
  • An "absolute" path in a metadata field (that typically would replace the whole URL path) is treated as a "relative" path (starting from the end of metadataBase).

For example, given the following metadataBase:

app/layout.tsx
import type { Metadata } from 'next'
 
export const metadata: Metadata = {
  metadataBase: new URL('https://acme.com'),
}

Any metadata fields that inherit the above metadataBase and set their own value will be resolved as follows:

metadata fieldResolved URL
/https://acme.com
./https://acme.com
paymentshttps://acme.com/payments
/paymentshttps://acme.com/payments
./paymentshttps://acme.com/payments
../paymentshttps://acme.com/payments
https://beta.acme.com/paymentshttps://beta.acme.com/payments

openGraph

layout.js | page.js
export const metadata = {
  openGraph: {
    title: 'Next.js',
    description: 'The React Framework for the Web',
    url: 'https://nextjs.org',
    siteName: 'Next.js',
    images: [
      {
        url: 'https://nextjs.org/og.png', // Must be an absolute URL
        width: 800,
        height: 600,
      },
      {
        url: 'https://nextjs.org/og-alt.png', // Must be an absolute URL
        width: 1800,
        height: 1600,
        alt: 'My custom alt',
      },
    ],
    videos: [
      {
        url: 'https://nextjs.org/video.mp4', // Must be an absolute URL
        width: 800,
        height: 600,
      },
    ],
    audio: [
      {
        url: 'https://nextjs.org/audio.mp3', // Must be an absolute URL
      },
    ],
    locale: 'en_US',
    type: 'website',
  },
}
<head> output
<meta property="og:title" content="Next.js" />
<meta property="og:description" content="The React Framework for the Web" />
<meta property="og:url" content="https://nextjs.org/" />
<meta property="og:site_name" content="Next.js" />
<meta property="og:locale" content="en_US" />
<meta property="og:image" content="https://nextjs.org/og.png" />
<meta property="og:image:width" content="800" />
<meta property="og:image:height" content="600" />
<meta property="og:image" content="https://nextjs.org/og-alt.png" />
<meta property="og:image:width" content="1800" />
<meta property="og:image:height" content="1600" />
<meta property="og:image:alt" content="My custom alt" />
<meta property="og:video" content="https://nextjs.org/video.mp4" />
<meta property="og:video:width" content="800" />
<meta property="og:video:height" content="600" />
<meta property="og:audio" content="https://nextjs.org/audio.mp3" />
<meta property="og:type" content="website" />
layout.js | page.js
export const metadata = {
  openGraph: {
    title: 'Next.js',
    description: 'The React Framework for the Web',
    type: 'article',
    publishedTime: '2023-01-01T00:00:00.000Z',
    authors: ['Seb', 'Josh'],
  },
}
<head> output
<meta property="og:title" content="Next.js" />
<meta property="og:description" content="The React Framework for the Web" />
<meta property="og:type" content="article" />
<meta property="article:published_time" content="2023-01-01T00:00:00.000Z" />
<meta property="article:author" content="Seb" />
<meta property="article:author" content="Josh" />

Good to know:

  • It may be more convenient to use the file-based Metadata API for Open Graph images. Rather than having to sync the config export with actual files, the file-based API will automatically generate the correct metadata for you.

robots

layout.tsx | page.tsx
import type { Metadata } from 'next'
 
export const metadata: Metadata = {
  robots: {
    index: true,
    follow: true,
    nocache: false,
    googleBot: {
      index: true,
      follow: true,
      noimageindex: false,
      'max-video-preview': -1,
      'max-image-preview': 'large',
      'max-snippet': -1,
    },
  },
}
<head> output
<meta name="robots" content="index, follow" />
<meta
  name="googlebot"
  content="index, follow, max-video-preview:-1, max-image-preview:large, max-snippet:-1"
/>

icons

Good to know: We recommend using the file-based Metadata API for icons where possible. Rather than having to sync the config export with actual files, the file-based API will automatically generate the correct metadata for you.

layout.js | page.js
export const metadata = {
  icons: {
    icon: '/icon.png',
    shortcut: '/shortcut-icon.png',
    apple: '/apple-icon.png',
    other: {
      rel: 'apple-touch-icon-precomposed',
      url: '/apple-touch-icon-precomposed.png',
    },
  },
}
<head> output
<link rel="shortcut icon" href="/shortcut-icon.png" />
<link rel="icon" href="/icon.png" />
<link rel="apple-touch-icon" href="/apple-icon.png" />
<link
  rel="apple-touch-icon-precomposed"
  href="/apple-touch-icon-precomposed.png"
/>
layout.js | page.js
export const metadata = {
  icons: {
    icon: [
      { url: '/icon.png' },
      new URL('/icon.png', 'https://example.com'),
      { url: '/icon-dark.png', media: '(prefers-color-scheme: dark)' },
    ],
    shortcut: ['/shortcut-icon.png'],
    apple: [
      { url: '/apple-icon.png' },
      { url: '/apple-icon-x3.png', sizes: '180x180', type: 'image/png' },
    ],
    other: [
      {
        rel: 'apple-touch-icon-precomposed',
        url: '/apple-touch-icon-precomposed.png',
      },
    ],
  },
}
<head> output
<link rel="shortcut icon" href="/shortcut-icon.png" />
<link rel="icon" href="/icon.png" />
<link rel="icon" href="https://example.com/icon.png" />
<link rel="icon" href="/icon-dark.png" media="(prefers-color-scheme: dark)" />
<link rel="apple-touch-icon" href="/apple-icon.png" />
<link
  rel="apple-touch-icon-precomposed"
  href="/apple-touch-icon-precomposed.png"
/>
<link
  rel="apple-touch-icon"
  href="/apple-icon-x3.png"
  sizes="180x180"
  type="image/png"
/>

Good to know: The msapplication-* meta tags are no longer supported in Chromium builds of Microsoft Edge, and thus no longer needed.

themeColor

Deprecated: The themeColor option in metadata is deprecated as of Next.js 14. Please use the viewport configuration instead.

colorScheme

Deprecated: The colorScheme option in metadata is deprecated as of Next.js 14. Please use the viewport configuration instead.

manifest

A web application manifest, as defined in the Web Application Manifest specification.

layout.js | page.js
export const metadata = {
  manifest: 'https://nextjs.org/manifest.json',
}
<head> output
<link rel="manifest" href="https://nextjs.org/manifest.json" />

twitter

The Twitter specification is (surprisingly) used for more than just X (formerly known as Twitter).

Learn more about the Twitter Card markup reference.

layout.js | page.js
export const metadata = {
  twitter: {
    card: 'summary_large_image',
    title: 'Next.js',
    description: 'The React Framework for the Web',
    siteId: '1467726470533754880',
    creator: '@nextjs',
    creatorId: '1467726470533754880',
    images: ['https://nextjs.org/og.png'], // Must be an absolute URL
  },
}
<head> output
<meta name="twitter:card" content="summary_large_image" />
<meta name="twitter:site:id" content="1467726470533754880" />
<meta name="twitter:creator" content="@nextjs" />
<meta name="twitter:creator:id" content="1467726470533754880" />
<meta name="twitter:title" content="Next.js" />
<meta name="twitter:description" content="The React Framework for the Web" />
<meta name="twitter:image" content="https://nextjs.org/og.png" />
layout.js | page.js
export const metadata = {
  twitter: {
    card: 'app',
    title: 'Next.js',
    description: 'The React Framework for the Web',
    siteId: '1467726470533754880',
    creator: '@nextjs',
    creatorId: '1467726470533754880',
    images: {
      url: 'https://nextjs.org/og.png',
      alt: 'Next.js Logo',
    },
    app: {
      name: 'twitter_app',
      id: {
        iphone: 'twitter_app://iphone',
        ipad: 'twitter_app://ipad',
        googleplay: 'twitter_app://googleplay',
      },
      url: {
        iphone: 'https://iphone_url',
        ipad: 'https://ipad_url',
      },
    },
  },
}
<head> output
<meta name="twitter:site:id" content="1467726470533754880" />
<meta name="twitter:creator" content="@nextjs" />
<meta name="twitter:creator:id" content="1467726470533754880" />
<meta name="twitter:title" content="Next.js" />
<meta name="twitter:description" content="The React Framework for the Web" />
<meta name="twitter:card" content="app" />
<meta name="twitter:image" content="https://nextjs.org/og.png" />
<meta name="twitter:image:alt" content="Next.js Logo" />
<meta name="twitter:app:name:iphone" content="twitter_app" />
<meta name="twitter:app:id:iphone" content="twitter_app://iphone" />
<meta name="twitter:app:id:ipad" content="twitter_app://ipad" />
<meta name="twitter:app:id:googleplay" content="twitter_app://googleplay" />
<meta name="twitter:app:url:iphone" content="https://iphone_url" />
<meta name="twitter:app:url:ipad" content="https://ipad_url" />
<meta name="twitter:app:name:ipad" content="twitter_app" />
<meta name="twitter:app:name:googleplay" content="twitter_app" />

viewport

Deprecated: The viewport option in metadata is deprecated as of Next.js 14. Please use the viewport configuration instead.

verification

layout.js | page.js
export const metadata = {
  verification: {
    google: 'google',
    yandex: 'yandex',
    yahoo: 'yahoo',
    other: {
      me: ['my-email', 'my-link'],
    },
  },
}
<head> output
<meta name="google-site-verification" content="google" />
<meta name="y_key" content="yahoo" />
<meta name="yandex-verification" content="yandex" />
<meta name="me" content="my-email" />
<meta name="me" content="my-link" />

appleWebApp

layout.js | page.js
export const metadata = {
  itunes: {
    appId: 'myAppStoreID',
    appArgument: 'myAppArgument',
  },
  appleWebApp: {
    title: 'Apple Web App',
    statusBarStyle: 'black-translucent',
    startupImage: [
      '/assets/startup/apple-touch-startup-image-768x1004.png',
      {
        url: '/assets/startup/apple-touch-startup-image-1536x2008.png',
        media: '(device-width: 768px) and (device-height: 1024px)',
      },
    ],
  },
}
<head> output
<meta
  name="apple-itunes-app"
  content="app-id=myAppStoreID, app-argument=myAppArgument"
/>
<meta name="mobile-web-app-capable" content="yes" />
<meta name="apple-mobile-web-app-title" content="Apple Web App" />
<link
  href="/assets/startup/apple-touch-startup-image-768x1004.png"
  rel="apple-touch-startup-image"
/>
<link
  href="/assets/startup/apple-touch-startup-image-1536x2008.png"
  media="(device-width: 768px) and (device-height: 1024px)"
  rel="apple-touch-startup-image"
/>
<meta
  name="apple-mobile-web-app-status-bar-style"
  content="black-translucent"
/>

alternates

layout.js | page.js
export const metadata = {
  alternates: {
    canonical: 'https://nextjs.org',
    languages: {
      'en-US': 'https://nextjs.org/en-US',
      'de-DE': 'https://nextjs.org/de-DE',
    },
    media: {
      'only screen and (max-width: 600px)': 'https://nextjs.org/mobile',
    },
    types: {
      'application/rss+xml': 'https://nextjs.org/rss',
    },
  },
}
<head> output
<link rel="canonical" href="https://nextjs.org" />
<link rel="alternate" hreflang="en-US" href="https://nextjs.org/en-US" />
<link rel="alternate" hreflang="de-DE" href="https://nextjs.org/de-DE" />
<link
  rel="alternate"
  media="only screen and (max-width: 600px)"
  href="https://nextjs.org/mobile"
/>
<link
  rel="alternate"
  type="application/rss+xml"
  href="https://nextjs.org/rss"
/>
layout.js | page.js
export const metadata = {
  appLinks: {
    ios: {
      url: 'https://nextjs.org/ios',
      app_store_id: 'app_store_id',
    },
    android: {
      package: 'com.example.android/package',
      app_name: 'app_name_android',
    },
    web: {
      url: 'https://nextjs.org/web',
      should_fallback: true,
    },
  },
}
<head> output
<meta property="al:ios:url" content="https://nextjs.org/ios" />
<meta property="al:ios:app_store_id" content="app_store_id" />
<meta property="al:android:package" content="com.example.android/package" />
<meta property="al:android:app_name" content="app_name_android" />
<meta property="al:web:url" content="https://nextjs.org/web" />
<meta property="al:web:should_fallback" content="true" />

archives

Describes a collection of records, documents, or other materials of historical interest (source).

layout.js | page.js
export const metadata = {
  archives: ['https://nextjs.org/13'],
}
<head> output
<link rel="archives" href="https://nextjs.org/13" />

assets

layout.js | page.js
export const metadata = {
  assets: ['https://nextjs.org/assets'],
}
<head> output
<link rel="assets" href="https://nextjs.org/assets" />

bookmarks

layout.js | page.js
export const metadata = {
  bookmarks: ['https://nextjs.org/13'],
}
<head> output
<link rel="bookmarks" href="https://nextjs.org/13" />

category

layout.js | page.js
export const metadata = {
  category: 'technology',
}
<head> output
<meta name="category" content="technology" />

facebook

You can connect a Facebook app or Facebook account to you webpage for certain Facebook Social Plugins Facebook Documentation

Good to know: You can specify either appId or admins, but not both.

layout.js | page.js
export const metadata = {
  facebook: {
    appId: '12345678',
  },
}
<head> output
<meta property="fb:app_id" content="12345678" />
layout.js | page.js
export const metadata = {
  facebook: {
    admins: '12345678',
  },
}
<head> output
<meta property="fb:admins" content="12345678" />

If you want to generate multiple fb:admins meta tags you can use array value.

layout.js | page.js
export const metadata = {
  facebook: {
    admins: ['12345678', '87654321'],
  },
}
<head> output
<meta property="fb:admins" content="12345678" />
<meta property="fb:admins" content="87654321" />

pinterest

You can enable or disable Pinterest Rich Pins on your webpage.

layout.js | page.js
export const metadata = {
  pinterest: {
    richPin: true,
  },
}
<head> output
<meta name="pinterest-rich-pin" content="true" />

other

All metadata options should be covered using the built-in support. However, there may be custom metadata tags specific to your site, or brand new metadata tags just released. You can use the other option to render any custom metadata tag.

layout.js | page.js
export const metadata = {
  other: {
    custom: 'meta',
  },
}
<head> output
<meta name="custom" content="meta" />

If you want to generate multiple same key meta tags you can use array value.

layout.js | page.js
export const metadata = {
  other: {
    custom: ['meta1', 'meta2'],
  },
}
<head> output
<meta name="custom" content="meta1" /> <meta name="custom" content="meta2" />

Unsupported Metadata

The following metadata types do not currently have built-in support. However, they can still be rendered in the layout or page itself.

Types

You can add type safety to your metadata by using the Metadata type. If you are using the built-in TypeScript plugin in your IDE, you do not need to manually add the type, but you can still explicitly add it if you want.

metadata object

layout.tsx | page.tsx
import type { Metadata } from 'next'
 
export const metadata: Metadata = {
  title: 'Next.js',
}

generateMetadata function

Regular function
layout.tsx | page.tsx
import type { Metadata } from 'next'
 
export function generateMetadata(): Metadata {
  return {
    title: 'Next.js',
  }
}
Async function
layout.tsx | page.tsx
import type { Metadata } from 'next'
 
export async function generateMetadata(): Promise<Metadata> {
  return {
    title: 'Next.js',
  }
}
With segment props
layout.tsx | page.tsx
import type { Metadata } from 'next'
 
type Props = {
  params: Promise<{ id: string }>
  searchParams: Promise<{ [key: string]: string | string[] | undefined }>
}
 
export function generateMetadata({ params, searchParams }: Props): Metadata {
  return {
    title: 'Next.js',
  }
}
 
export default function Page({ params, searchParams }: Props) {}
With parent metadata
layout.tsx | page.tsx
import type { Metadata, ResolvingMetadata } from 'next'
 
export async function generateMetadata(
  { params, searchParams }: Props,
  parent: ResolvingMetadata
): Promise<Metadata> {
  return {
    title: 'Next.js',
  }
}
JavaScript Projects

For JavaScript projects, you can use JSDoc to add type safety.

layout.js | page.js
/** @type {import("next").Metadata} */
export const metadata = {
  title: 'Next.js',
}
MetadataRecommendation
<meta http-equiv="...">Use appropriate HTTP Headers via redirect(), Middleware, Security Headers
<base>Render the tag in the layout or page itself.
<noscript>Render the tag in the layout or page itself.
<style>Learn more about styling in Next.js.
<script>Learn more about using scripts.
<link rel="stylesheet" />import stylesheets directly in the layout or page itself.
<link rel="preload />Use ReactDOM preload method
<link rel="preconnect" />Use ReactDOM preconnect method
<link rel="dns-prefetch" />Use ReactDOM prefetchDNS method

Resource hints

The <link> element has a number of rel keywords that can be used to hint to the browser that an external resource is likely to be needed. The browser uses this information to apply preloading optimizations depending on the keyword.

While the Metadata API doesn't directly support these hints, you can use new ReactDOM methods to safely insert them into the <head> of the document.

app/preload-resources.tsx
'use client'
 
import ReactDOM from 'react-dom'
 
export function PreloadResources() {
  ReactDOM.preload('...', { as: '...' })
  ReactDOM.preconnect('...', { crossOrigin: '...' })
  ReactDOM.prefetchDNS('...')
 
  return '...'
}

Start loading a resource early in the page rendering (browser) lifecycle. MDN Docs.

ReactDOM.preload(href: string, options: { as: string })
<head> output
<link rel="preload" href="..." as="..." />

Preemptively initiate a connection to an origin. MDN Docs.

ReactDOM.preconnect(href: string, options?: { crossOrigin?: string })
<head> output
<link rel="preconnect" href="..." crossorigin />

Attempt to resolve a domain name before resources get requested. MDN Docs.

ReactDOM.prefetchDNS(href: string)
<head> output
<link rel="dns-prefetch" href="..." />

Good to know:

  • These methods are currently only supported in Client Components, which are still Server Side Rendered on initial page load.
  • Next.js in-built features such as next/font, next/image and next/script automatically handle relevant resource hints.

Behavior

Default Fields

There are two default meta tags that are always added even if a route doesn't define metadata:

  • The meta charset tag sets the character encoding for the website.
  • The meta viewport tag sets the viewport width and scale for the website to adjust for different devices.
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1" />

Good to know: You can overwrite the default viewport meta tag.

Streaming metadata

Metadata returned by generateMetadata is streamed to the client. This allows Next.js to inject metadata into the HTML as soon as it's resolved.

Since page metadata primarily targets bots and crawlers, Next.js will stream metadata for bots that can execute JavaScript and inspect the full page DOM (e.g. Googlebot). However, metadata will continue blocking the render of the page for HTML-limited bots (e.g. Twitterbot) as these cannot execute JavaScript while crawling.

Next.js automatically detects the user agent of incoming requests to determine whether to serve streaming metadata or fallback to blocking metadata.

If you need to customize this list, you can define them manually using the htmlLimitedBots option in next.config.js. Next.js will ensure user agents matching this regex receive blocking metadata when requesting your web page.

next.config.ts
import type { NextConfig } from 'next'
 
const config: NextConfig = {
  htmlLimitedBots: /MySpecialBot|MyAnotherSpecialBot|SimpleCrawler/,
}
 
export default config

Specifying a htmlLimitedBots config will override the Next.js' default list, allowing you full control over what user agents should opt into this behavior. This is advanced behavior, and the default should be sufficient for most cases.

Ordering

Metadata is evaluated in order, starting from the root segment down to the segment closest to the final page.js segment. For example:

  1. app/layout.tsx (Root Layout)
  2. app/blog/layout.tsx (Nested Blog Layout)
  3. app/blog/[slug]/page.tsx (Blog Page)

Merging

Following the evaluation order, Metadata objects exported from multiple segments in the same route are shallowly merged together to form the final metadata output of a route. Duplicate keys are replaced based on their ordering.

This means metadata with nested fields such as openGraph and robots that are defined in an earlier segment are overwritten by the last segment to define them.

Overwriting fields

app/layout.js
export const metadata = {
  title: 'Acme',
  openGraph: {
    title: 'Acme',
    description: 'Acme is a...',
  },
}
app/blog/page.js
export const metadata = {
  title: 'Blog',
  openGraph: {
    title: 'Blog',
  },
}
 
// Output:
// <title>Blog</title>
// <meta property="og:title" content="Blog" />

In the example above:

  • title from app/layout.js is replaced by title in app/blog/page.js.
  • All openGraph fields from app/layout.js are replaced in app/blog/page.js because app/blog/page.js sets openGraph metadata. Note the absence of openGraph.description.

If you'd like to share some nested fields between segments while overwriting others, you can pull them out into a separate variable:

app/shared-metadata.js
export const openGraphImage = { images: ['http://...'] }
app/page.js
import { openGraphImage } from './shared-metadata'
 
export const metadata = {
  openGraph: {
    ...openGraphImage,
    title: 'Home',
  },
}
app/about/page.js
import { openGraphImage } from '../shared-metadata'
 
export const metadata = {
  openGraph: {
    ...openGraphImage,
    title: 'About',
  },
}

In the example above, the OG image is shared between app/layout.js and app/about/page.js while the titles are different.

Inheriting fields

app/layout.js
export const metadata = {
  title: 'Acme',
  openGraph: {
    title: 'Acme',
    description: 'Acme is a...',
  },
}
app/about/page.js
export const metadata = {
  title: 'About',
}
 
// Output:
// <title>About</title>
// <meta property="og:title" content="Acme" />
// <meta property="og:description" content="Acme is a..." />

Notes

  • title from app/layout.js is replaced by title in app/about/page.js.
  • All openGraph fields from app/layout.js are inherited in app/about/page.js because app/about/page.js doesn't set openGraph metadata.

Version History

VersionChanges
v15.2.0Introduced streaming support to generateMetadata.
v13.2.0viewport, themeColor, and colorScheme deprecated in favor of the viewport configuration.
v13.2.0metadata and generateMetadata introduced.

Next Steps

View all the Metadata API options.

Metadata Files

API documentation for the metadata file conventions.

generateViewport

API Reference for the generateViewport function.