What is dynamic metadata?

Next.jsMiddle~1 min read

Dynamic metadata in Next.js is metadata that gets computed at request time and can depend on the route, data, the user, or external sources.

Put simply:

dynamic metadata is SEO data that adapts to a specific page and its context.

How dynamic metadata is defined

Dynamic metadata is described via the generateMetadata function:

export async function generateMetadata({ params }) {
  return {
    title: `Post: ${params.slug}`,
    description: 'Article description'
  }
}

Next.js calls this function on the server before rendering the page or layout.

Where the data comes from

Inside generateMetadata you can use:

params (dynamic route segments)
searchParams
fetch to an API or a database
request-level information

This lets you build metadata based on the real content.

Where dynamic metadata works

Dynamic metadata can be used in:

page.tsx
layout.tsx
nested layouts
route groups

Just like layouts, it's inherited and overridden.

When dynamic metadata is needed

Dynamic metadata is needed when:

the URL contains parameters (/blog/[slug])
each page has unique content
SEO depends on the data
a CMS or an API is used
different Open Graph images are needed

Examples:

a blog
product cards
user profiles
categories with different content

An example with data loading

export async function generateMetadata({ params }) {
  const post = await fetchPost(params.slug)

  return {
    title: post.title,
    description: post.excerpt,
    openGraph: {
      images: [post.cover]
    }
  }
}

The metadata is built based on the real post data.

Impact on performance

Dynamic metadata:

runs on the server
can make requests
adds a small cost to rendering

But:

it's cached the same way as fetch
it works correctly with ISR and SSR
it gives precise SEO

Difference from static metadata

Static metadata	Dynamic metadata
A `metadata` object	A `generateMetadata` function
Fixed data	Computed data
Faster	A bit heavier
No logic	You can write code
For static pages	For dynamic routes

Summary

Dynamic metadata is:

server-side metadata with logic
SEO tied to data
support for dynamic URLs
correct behavior with the App Router

Short Answer

Interview ready

Premium

A concise answer to help you respond confidently on this topic during an interview.