generateStaticParams

The generateStaticParams function can be used in combination with dynamic route segments to statically generate routes at build time instead of on-demand at request time.

app/blog/[slug]/page.js

// Return a list of `params` to populate the [slug] dynamic segment
export async function generateStaticParams() {
  const posts = await fetch('https://.../posts').then((res) => res.json())

  return posts.map((post) => ({
    slug: post.slug,
  }))
}

// Multiple versions of this page will be statically generated
// using the `params` returned by `generateStaticParams`
export default function Page({ params }) {
  const { slug } = params
  // ...
}

Good to know

You can use the dynamicParams segment config option to control what happens when a dynamic segment is visited that was not generated with generateStaticParams.

During next dev, generateStaticParams will be called when you navigate to a route.

During next build, generateStaticParams runs before the corresponding Layouts or Pages are generated.

During revalidation (ISR), generateStaticParams will not be called again.

generateStaticParams replaces the getStaticPaths function in the Pages Router.

Parameters

options.params (optional)

If multiple dynamic segments in a route use generateStaticParams, the child generateStaticParams function is executed once for each set of params the parent generates.

The params object contains the populated params from the parent generateStaticParams, which can be used to generate the params in a child segment.

Returns

generateStaticParams should return an array of objects where each object represents the populated dynamic segments of a single route.

Each property in the object is a dynamic segment to be filled in for the route.
The properties name is the segment's name, and the properties value is what that segment should be filled in with.

Example Route	`generateStaticParams` Return Type
`/product/[id]`	`{ id: string }[]`
`/products/[category]/[product]`	`{ category: string, product: string }[]`
`/products/[...slug]`	`{ slug: string[] }[]`

Single Dynamic Segment

export function generateStaticParams() {
  return [{ id: '1' }, { id: '2' }, { id: '3' }]
}

// Three versions of this page will be statically generated
// using the `params` returned by `generateStaticParams`
// - /product/1
// - /product/2
// - /product/3
export default function Page({ params }: { params: { id: string } }) {
  const { id } = params
  // ...
}

export function generateStaticParams() {
  return [{ id: '1' }, { id: '2' }, { id: '3' }]
}

// Three versions of this page will be statically generated
// using the `params` returned by `generateStaticParams`
// - /product/1
// - /product/2
// - /product/3
export default function Page({ params }) {
  const { id } = params
  // ...
}

Multiple Dynamic Segments

export function generateStaticParams() {
  return [
    { category: 'a', product: '1' },
    { category: 'b', product: '2' },
    { category: 'c', product: '3' },
  ]
}

// Three versions of this page will be statically generated
// using the `params` returned by `generateStaticParams`
// - /products/a/1
// - /products/b/2
// - /products/c/3
export default function Page({
  params,
}: {
  params: { category: string; product: string }
}) {
  const { category, product } = params
  // ...
}

export function generateStaticParams() {
  return [
    { category: 'a', product: '1' },
    { category: 'b', product: '2' },
    { category: 'c', product: '3' },
  ]
}

// Three versions of this page will be statically generated
// using the `params` returned by `generateStaticParams`
// - /products/a/1
// - /products/b/2
// - /products/c/3
export default function Page({ params }) {
  const { category, product } = params
  // ...
}

Catch-all Dynamic Segment

export function generateStaticParams() {
  return [{ slug: ['a', '1'] }, { slug: ['b', '2'] }, { slug: ['c', '3'] }]
}

// Three versions of this page will be statically generated
// using the `params` returned by `generateStaticParams`
// - /product/a/1
// - /product/b/2
// - /product/c/3
export default function Page({ params }: { params: { slug: string[] } }) {
  const { slug } = params
  // ...
}

export function generateStaticParams() {
  return [{ slug: ['a', '1'] }, { slug: ['b', '2'] }, { slug: ['c', '3'] }]
}

// Three versions of this page will be statically generated
// using the `params` returned by `generateStaticParams`
// - /product/a/1
// - /product/b/2
// - /product/c/3
export default function Page({ params }) {
  const { slug } = params
  // ...
}

Examples

Multiple Dynamic Segments in a Route

You can generate params for dynamic segments above the current layout or page, but not below. For example, given the app/products/[category]/[product] route:

app/products/[category]/[product]/page.js can generate params for both [category] and [product].
app/products/[category]/layout.js can only generate params for [category].

There are two approaches to generating params for a route with multiple dynamic segments:

Generate params from the bottom up

Generate multiple dynamic segments from the child route segment.

// Generate segments for both [category] and [product]
export async function generateStaticParams() {
  const products = await fetch('https://.../products').then((res) => res.json())

  return products.map((product) => ({
    category: product.category.slug,
    product: product.id,
  }))
}

export default function Page({
  params,
}: {
  params: { category: string; product: string }
}) {
  // ...
}

// Generate segments for both [category] and [product]
export async function generateStaticParams() {
  const products = await fetch('https://.../products').then((res) => res.json())

  return products.map((product) => ({
    category: product.category.slug,
    product: product.id,
  }))
}

export default function Page({ params }) {
  // ...
}

Generate params from the top down

Generate the parent segments first and use the result to generate the child segments.

// Generate segments for [category]
export async function generateStaticParams() {
  const products = await fetch('https://.../products').then((res) => res.json())

  return products.map((product) => ({
    category: product.category.slug,
  }))
}

export default function Layout({ params }: { params: { category: string } }) {
  // ...
}

// Generate segments for [category]
export async function generateStaticParams() {
  const products = await fetch('https://.../products').then((res) => res.json())

  return products.map((product) => ({
    category: product.category.slug,
  }))
}

export default function Layout({ params }) {
  // ...
}

A child route segment's generateStaticParams function is executed once for each segment a parent generateStaticParams generates.

The child generateStaticParams function can use the params returned from the parent generateStaticParams function to dynamically generate its own segments.

// Generate segments for [product] using the `params` passed from
// the parent segment's `generateStaticParams` function
export async function generateStaticParams({
  params: { category },
}: {
  params: { category: string }
}) {
  const products = await fetch(
    `https://.../products?category=${category}`
  ).then((res) => res.json())

  return products.map((product) => ({
    product: product.id,
  }))
}

export default function Page({
  params,
}: {
  params: { category: string; product: string }
}) {
  // ...
}

// Generate segments for [product] using the `params` passed from
// the parent segment's `generateStaticParams` function
export async function generateStaticParams({ params: { category } }) {
  const products = await fetch(
    `https://.../products?category=${category}`
  ).then((res) => res.json())

  return products.map((product) => ({
    product: product.id,
  }))
}

export default function Page({ params }) {
  // ...
}

Good to know: fetch requests are automatically memoized for the same data across all generate-prefixed functions, Layouts, Pages, and Server Components. React cache can be used if fetch is unavailable.

Generate only a subset of params

You can generate a subset of params for a route by returning an array of objects with only the dynamic segments you want to generate. Then, by using the dynamicParams segment config option, you can control what happens when a dynamic segment is visited that was not generated with generateStaticParams.

app/blog/[slug]/page.js

// All posts besides the top 10 will be a 404
export const dynamicParams = false

export async function generateStaticParams() {
  const posts = await fetch('https://.../posts').then((res) => res.json())
  const topPosts = posts.slice(0, 10)

  return topPosts.map((post) => ({
    slug: post.slug,
  }))
}

Version History

Version	Changes
`v13.0.0`	`generateStaticParams` introduced.

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