use cache

The use cache directive allows you to mark a route, React component, or a function as cacheable. It can be used at the top of a file to indicate that all exports in the file should be cached, or inline at the top of function or component to cache the return value.

Usage

use cache is currently an experimental feature. To enable it, add the useCache option to your next.config.ts file:

import type { NextConfig } from 'next'
 
const nextConfig: NextConfig = {
  experimental: {
    useCache: true,
  },
}
 
export default nextConfig

Good to know: use cache can also be enabled with the dynamicIO option.

Then, add use cache at the file, component, or function level:

// File level
'use cache'
 
export default async function Page() {
  // ...
}
 
// Component level
export async function MyComponent() {
  'use cache'
  return <></>
}
 
// Function level
export async function getData() {
  'use cache'
  const data = await fetch('/api/data')
  return data
}

How use cache works

Cache keys

A cache entry's key is generated using a serialized version of its inputs, which includes:

• Build ID (generated for each build)
• Function ID (a secure identifier unique to the function)
• The serializable function arguments (or props).

The arguments passed to the cached function, as well as any values it reads from the parent scope automatically become a part of the key. This means, the same cache entry will be reused as long as its inputs are the same.

Non-serializable arguments

Any non-serializable arguments, props, or closed-over values will turn into references inside the cached function, and can be only passed through and not inspected nor modified. These non-serializable values will be filled in at the request time and won't become a part of the cache key.

For example, a cached function can take in JSX as a children prop and return <div>{children}</div>, but it won't be able to introspect the actual children object. This allows you to nest uncached content inside a cached component.

function CachedComponent({ children }: { children: ReactNode }) {
  'use cache'
  return <div>{children}</div>
}

Return values

The return value of the cacheable function must be serializable. This ensures that the cached data can be stored and retrieved correctly.

use cache at build time

When used at the top of a layout or page, the route segment will be prerendered, allowing it to later be revalidated.

This means use cache cannot be used with request-time APIs like cookies or headers.

use cache at runtime

On the server, the cache entries of individual components or functions will be cached in-memory.

Then, on the client, any content returned from the server cache will be stored in the browser's memory for the duration of the session or until revalidated.

During revalidation

By default, use cache has server-side revalidation period of 15 minutes. While this period may be useful for content that doesn't require frequent updates, you can use the cacheLife and cacheTag APIs to configure when the individual cache entries should be revalidated.

• cacheLife: Configure the cache entry lifetime.
• cacheTag: Create tags for on-demand revalidation.

Both of these APIs integrate across the client and server caching layers, meaning you can configure your caching semantics in one place and have them apply everywhere.

See the cacheLife and cacheTag API docs for more information.

Examples

Caching an entire route with use cache

To prerender an entire route, add use cache to the top of both the layout and page files. Each of these segments are treated as separate entry points in your application, and will be cached independently.

'use cache'
 
export default function Layout({ children }: { children: ReactNode }) {
  return <div>{children}</div>
}

Any components imported and nested in page file will inherit the cache behavior of page.

'use cache'
 
async function Users() {
  const users = await fetch('/api/users')
  // loop through users
}
 
export default function Page() {
  return (
    <main>
      <Users />
    </main>
  )
}

Good to know:

• If use cache is added only to the layout or the page, only that route segment and any components imported into it will be cached.
• If any of the nested children in the route use Dynamic APIs, then the route will opt out of prerendering.

Caching a component's output with use cache

You can use use cache at the component level to cache any fetches or computations performed within that component. The cache entry will be reused as long as the serialized props produce the same value in each instance.

export async function Bookings({ type = 'haircut' }: BookingsProps) {
  'use cache'
  async function getBookingsData() {
    const data = await fetch(`/api/bookings?type=${encodeURIComponent(type)}`)
    return data
  }
  return //...
}
 
interface BookingsProps {
  type: string
}

Caching function output with use cache

Since you can add use cache to any asynchronous function, you aren't limited to caching components or routes only. You might want to cache a network request, a database query, or a slow computation.

export async function getData() {
  'use cache'
 
  const data = await fetch('/api/data')
  return data
}

Interleaving

If you need to pass non-serializable arguments to a cacheable function, you can pass them as children. This means the children reference can change without affecting the cache entry.

export default async function Page() {
  const uncachedData = await getData()
  return (
    <CacheComponent>
      <DynamicComponent data={uncachedData} />
    </CacheComponent>
  )
}
 
async function CacheComponent({ children }: { children: ReactNode }) {
  'use cache'
  const cachedData = await fetch('/api/cached-data')
  return (
    <div>
      <PrerenderedComponent data={cachedData} />
      {children}
    </div>
  )
}

You can also pass Server Actions through cached components to Client Components without invoking them inside the cacheable function.

import ClientComponent from './ClientComponent'
 
export default async function Page() {
  const performUpdate = async () => {
    'use server'
    // Perform some server-side update
    await db.update(...)
  }
 
  return <CacheComponent performUpdate={performUpdate} />
}
 
async function CachedComponent({
  performUpdate,
}: {
  performUpdate: () => Promise<void>
}) {
  'use cache'
  // Do not call performUpdate here
  return <ClientComponent action={performUpdate} />
}

'use client'
 
export default function ClientComponent({
  action,
}: {
  action: () => Promise<void>
}) {
  return <button onClick={action}>Update</button>
}