ββββββββββββββββββββββββββββββββββββββββββββββββββββββββββββ β π nextjs/app/api-reference/functions/generate-metadata β ββββββββββββββββββββββββββββββββββββββββββββββββββββββββββββ
ββββββββββββββββββββββββββββββββββββββββββββββββββββββββββββββββββββββββββββββββββββββββββββββββ
β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β β
You can use the metadata object or the generateMetadata function to define metadata.
metadata objectTo define static metadata, export a Metadata object from a layout.js or page.js file.
import type { Metadata } from 'next'
export const metadata: Metadata = {
title: '...',
description: '...',
}
export default function Page() {}
export const metadata = {
title: '...',
description: '...',
}
export default function Page() {}
See the Metadata Fields for a complete list of supported options.
generateMetadata functionDynamic 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.
Resolving generateMetadata is part of rendering the page. If the page can be pre-rendered and generateMetadata doesn't introduce dynamic behavior, the resulting metadata is included in the pageβs initial HTML.
Otherwise the metadata resolved from generateMetadata can be streamed after sending the initial UI.
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://.../${id}`).then((res) => res.json())
// optionally access and extend (rather than replace) parent metadata
const previousImages = (await parent).openGraph?.images || []
return {
title: product.title,
openGraph: {
images: ['/some-specific-page-image.jpg', ...previousImages],
},
}
}
export default function Page({ params, searchParams }: Props) {}
export async function generateMetadata({ params, searchParams }, parent) {
// read route params
const { id } = await params
// fetch data
const product = await fetch(`https://.../${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 }) {}
For type completion of params and searchParams, you can type the first argument with PageProps<'/route'> or LayoutProps<'/route'> for pages and layouts respectively.
Good to know:
- Metadata can be added to
layout.jsandpage.jsfiles.- Next.js will automatically resolve the metadata, and create the relevant
<head>tags for the page.- The
metadataobject andgenerateMetadatafunction exports are only supported in Server Components.- You cannot export both the
metadataobject andgenerateMetadatafunction from the same route segment.fetchrequests insidegenerateMetadataare automatically memoized for the same data acrossgenerateMetadata,generateStaticParams, Layouts, Pages, and Server Components.- React
cachecan be used iffetchis unavailable.- File-based metadata has the higher priority and will override the
metadataobject andgenerateMetadatafunction.
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:
| Route | URL | params |
| ------------------------------- | ----------- | ------------------------- |
| 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:
| URL | searchParams |
| --------------- | -------------------- |
| /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.
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
metadataobject rather thangenerateMetadata.fetchrequests are automatically memoized for the same data acrossgenerateMetadata,generateStaticParams, Layouts, Pages, and Server Components. Reactcachecan be used iffetchis unavailable.searchParamsare only available inpage.jssegments.- The
redirect()andnotFound()Next.js methods can also be used insidegenerateMetadata.
The following fields are supported:
titleThe title attribute is used to set the title of the document. It can be defined as a simple string or an optional template object.
export const metadata = {
title: 'Next.js',
}
<title>Next.js</title>
defaulttitle.default can be used to provide a fallback title to child route segments that don't define a title.
import type { Metadata } from 'next'
export const metadata: Metadata = {
title: {
default: 'Acme',
},
}
import type { Metadata } from 'next'
export const metadata: Metadata = {}
// Output: <title>Acme</title>
templatetitle.template can be used to add a prefix or a suffix to titles defined in child route segments.
import type { Metadata } from 'next'
export const metadata: Metadata = {
title: {
template: '%s | Acme',
default: 'Acme', // a default is required when creating a template
},
}
export const metadata = {
title: {
template: '%s | Acme',
default: 'Acme', // a default is required when creating a template
},
}
import type { Metadata } from 'next'
export const metadata: Metadata = {
title: 'About',
}
// Output: <title>About | Acme</title>
export const metadata = {
title: 'About',
}
// Output: <title>About | Acme</title>
Good to know:
title.templateapplies to child route segments and not the segment it's defined in. This means:
title.defaultis required when you add atitle.template.title.templatedefined inlayout.jswill not apply to atitledefined in apage.jsof the same route segment.title.templatedefined inpage.jshas no effect because a page is always the terminating segment (it doesn't have any children route segments).title.templatehas no effect if a route has not defined atitleortitle.default.
absolutetitle.absolute can be used to provide a title that ignores title.template set in parent segments.
import type { Metadata } from 'next'
export const metadata: Metadata = {
title: {
template: '%s | Acme',
},
}
export const metadata = {
title: {
template: '%s | Acme',
},
}
import type { Metadata } from 'next'
export const metadata: Metadata = {
title: {
absolute: 'About',
},
}
// Output: <title>About</title>
export const metadata = {
title: {
absolute: 'About',
},
}
// Output: <title>About</title>
Good to know:
layout.js
title(string) andtitle.defaultdefine the default title for child segments (that do not define their owntitle). It will augmenttitle.templatefrom the closest parent segment if it exists.title.absolutedefines the default title for child segments. It ignorestitle.templatefrom parent segments.title.templatedefines 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 augmenttitle.templatefrom the closest parent segment if it exists.title.absolutedefines the route title. It ignorestitle.templatefrom parent segments.title.templatehas no effect inpage.jsbecause a page is always the terminating segment of a route.
descriptionexport const metadata = {
description: 'The React Framework for the Web',
}
<meta name="description" content="The React Framework for the Web" />
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 MarkbΓ₯ge',
formatDetection: {
email: false,
address: false,
telephone: false,
},
}
<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 MarkbΓ₯ge" />
<meta name="format-detection" content="telephone=no, address=no, email=no" />
metadataBasemetadataBase 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.metadataBase to form a fully qualified URL.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',
},
}
<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:
metadataBaseis typically set in rootapp/layout.jsto apply to URL-basedmetadatafields across all routes.- All URL-based
metadatafields that require absolute URLs can be configured with ametadataBaseoption.metadataBasecan contain a subdomain e.g.https://app.acme.comor base path e.g.https://acme.com/start/from/here- If a
metadatafield provides an absolute URL,metadataBasewill be ignored.- Using a relative path in a URL-based
metadatafield without configuring ametadataBasewill 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 favors developer intent over default directory traversal semantics.
metadataBase and metadata fields are normalized.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:
import type { Metadata } from 'next'
export const metadata: Metadata = {
metadataBase: new URL('https://acme.com'),
}
export const 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 field | Resolved URL |
| -------------------------------- | -------------------------------- |
| / | https://acme.com |
| ./ | https://acme.com |
| payments | https://acme.com/payments |
| /payments | https://acme.com/payments |
| ./payments | https://acme.com/payments |
| ../payments | https://acme.com/payments |
| https://beta.acme.com/payments | https://beta.acme.com/payments |
openGraphexport 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',
},
}
<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" />
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'],
},
}
<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.
robotsimport 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,
},
},
}
<meta name="robots" content="index, follow" />
<meta
name="googlebot"
content="index, follow, max-video-preview:-1, max-image-preview:large, max-snippet:-1"
/>
iconsGood 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.
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',
},
},
}
<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"
/>
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',
},
],
},
}
<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.
themeColorDeprecated: The
themeColoroption inmetadatais deprecated as of Next.js 14. Please use theviewportconfiguration instead.
colorSchemeDeprecated: The
colorSchemeoption inmetadatais deprecated as of Next.js 14. Please use theviewportconfiguration instead.
manifestA web application manifest, as defined in the Web Application Manifest specification.
export const metadata = {
manifest: 'https://nextjs.org/manifest.json',
}
<link rel="manifest" href="https://nextjs.org/manifest.json" />
twitterThe Twitter specification is (surprisingly) used for more than just X (formerly known as Twitter).
Learn more about the Twitter Card markup reference.
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
},
}
<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" />
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',
},
},
},
}
<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" />
viewportDeprecated: The
viewportoption inmetadatais deprecated as of Next.js 14. Please use theviewportconfiguration instead.
verificationexport const metadata = {
verification: {
google: 'google',
yandex: 'yandex',
yahoo: 'yahoo',
other: {
me: ['my-email', 'my-link'],
},
},
}
<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" />
appleWebAppexport 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)',
},
],
},
}
<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"
/>
alternatesexport 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',
},
},
}
<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"
/>
appLinksexport 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,
},
},
}
<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" />
archivesDescribes a collection of records, documents, or other materials of historical interest (source).
export const metadata = {
archives: ['https://nextjs.org/13'],
}
<link rel="archives" href="https://nextjs.org/13" />
assetsexport const metadata = {
assets: ['https://nextjs.org/assets'],
}
<link rel="assets" href="https://nextjs.org/assets" />
bookmarksexport const metadata = {
bookmarks: ['https://nextjs.org/13'],
}
<link rel="bookmarks" href="https://nextjs.org/13" />
categoryexport const metadata = {
category: 'technology',
}
<meta name="category" content="technology" />
facebookYou can connect a Facebook app or Facebook account to your webpage for certain Facebook Social Plugins Facebook Documentation
Good to know: You can specify either appId or admins, but not both.
export const metadata = {
facebook: {
appId: '12345678',
},
}
<meta property="fb:app_id" content="12345678" />
export const metadata = {
facebook: {
admins: '12345678',
},
}
<meta property="fb:admins" content="12345678" />
If you want to generate multiple fb:admins meta tags you can use array value.
export const metadata = {
facebook: {
admins: ['12345678', '87654321'],
},
}
<meta property="fb:admins" content="12345678" />
<meta property="fb:admins" content="87654321" />
pinterestYou can enable or disable Pinterest Rich Pins on your webpage.
export const metadata = {
pinterest: {
richPin: true,
},
}
<meta name="pinterest-rich-pin" content="true" />
otherAll 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.
export const metadata = {
other: {
custom: 'meta',
},
}
<meta name="custom" content="meta" />
If you want to generate multiple same key meta tags you can use array value.
export const metadata = {
other: {
custom: ['meta1', 'meta2'],
},
}
<meta name="custom" content="meta1" /> <meta name="custom" content="meta2" />
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 objectimport type { Metadata } from 'next'
export const metadata: Metadata = {
title: 'Next.js',
}
generateMetadata functionimport type { Metadata } from 'next'
export function generateMetadata(): Metadata {
return {
title: 'Next.js',
}
}
import type { Metadata } from 'next'
export async function generateMetadata(): Promise<Metadata> {
return {
title: 'Next.js',
}
}
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) {}
import type { Metadata, ResolvingMetadata } from 'next'
export async function generateMetadata(
{ params, searchParams }: Props,
parent: ResolvingMetadata
): Promise<Metadata> {
return {
title: 'Next.js',
}
}
For JavaScript projects, you can use JSDoc to add type safety.
/** @type {import("next").Metadata} */
export const metadata = {
title: 'Next.js',
}
The following metadata types do not currently have built-in support. However, they can still be rendered in the layout or page itself.
| Metadata | Recommendation |
| ----------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| <meta http-equiv="..."> | Use appropriate HTTP Headers via redirect(), Proxy, 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 |
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.
'use client'
import ReactDOM from 'react-dom'
export function PreloadResources() {
ReactDOM.preload('...', { as: '...' })
ReactDOM.preconnect('...', { crossOrigin: '...' })
ReactDOM.prefetchDNS('...')
return '...'
}
'use client'
import ReactDOM from 'react-dom'
export function PreloadResources() {
ReactDOM.preload('...', { as: '...' })
ReactDOM.preconnect('...', { crossOrigin: '...' })
ReactDOM.prefetchDNS('...')
return '...'
}
<link rel="preload">Start loading a resource early in the page rendering (browser) lifecycle. MDN Docs.
ReactDOM.preload(href: string, options: { as: string })
<link rel="preload" href="..." as="..." />
<link rel="preconnect">Preemptively initiate a connection to an origin. MDN Docs.
ReactDOM.preconnect(href: string, options?: { crossOrigin?: string })
<link rel="preconnect" href="..." crossorigin />
<link rel="dns-prefetch">Attempt to resolve a domain name before resources get requested. MDN Docs.
ReactDOM.prefetchDNS(href: string)
<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/imageandnext/scriptautomatically handle relevant resource hints.
There are two default meta tags that are always added even if a route doesn't define metadata:
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1" />
Good to know: You can overwrite the default
viewportmeta tag.
Streaming metadata allows Next.js to render and send the initial UI to the browser, without waiting for generateMetadata to complete.
When generateMetadata resolves, the resulting metadata tags are appended to the <body> tag. We have verified that metadata is interpreted correctly by bots that execute JavaScript and inspect the full DOM (e.g. Googlebot).
For HTML-limited bots that canβt execute JavaScript (e.g. facebookexternalhit), metadata continues to block page rendering. The resulting metadata will be available in the <head> tag.
Next.js automatically detects HTML-limited bots by looking at the User Agent header. You can use the htmlLimitedBots option in your Next.js config file to override the default User Agent list.
To fully disable streaming metadata:
import type { NextConfig } from 'next'
const config: NextConfig = {
htmlLimitedBots: /.*/,
}
export default config
module.exports = {
htmlLimitedBots: /.*/,
}
Streaming metadata improves perceived performance by reducing TTFB and can help lowering LCP time.
Overriding htmlLimitedBots could lead to longer response times. Streaming metadata is an advanced feature, and the default should be sufficient for most cases.
Metadata is evaluated in order, starting from the root segment down to the segment closest to the final page.js segment. For example:
app/layout.tsx (Root Layout)app/blog/layout.tsx (Nested Blog Layout)app/blog/[slug]/page.tsx (Blog Page)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.
export const metadata = {
title: 'Acme',
openGraph: {
title: 'Acme',
description: 'Acme is a...',
},
}
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.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:
export const openGraphImage = { images: ['http://...'] }
import { openGraphImage } from './shared-metadata'
export const metadata = {
openGraph: {
...openGraphImage,
title: 'Home',
},
}
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.
export const metadata = {
title: 'Acme',
openGraph: {
title: 'Acme',
description: 'Acme is a...',
},
}
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.openGraph fields from app/layout.js are inherited in app/about/page.js because app/about/page.js doesn't set openGraph metadata.| Version | Changes |
| --------- | ------------------------------------------------------------------------------------------------------------------------------------------------------- |
| v15.2.0 | Introduced streaming support to generateMetadata. |
| v13.2.0 | viewport, themeColor, and colorScheme deprecated in favor of the viewport configuration. |
| v13.2.0 | metadata and generateMetadata introduced. |
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