---
title: "Invalid `use cache: private` composition"
url: "https://nextjs.org/docs/messages/use-cache-private-composition"
docs_index: /docs/llms.txt
---



## Why This Error Occurred

The `use cache: private` directive lets a cached function access request-specific data. Next.js stores its results only in the browser's memory. Private cached functions cannot run inside shared caches or without an active request. This error occurs when a private cached function is:

- **Nested inside a public `use cache` directive.** A shared cached function can reuse its result across users, so it cannot contain a private cached function. Nest a private cached function only inside another private cached function.
- **Used inside `unstable_cache()`.** `unstable_cache()` is a shared cache and has the same restriction.
- **Used without an active request.** A private cached function depends on the current request, so it cannot run during build-time contexts such as `generateStaticParams`.

```jsx filename="app/page.js" highlight={2,7}
async function PrivateSegment() {
  'use cache: private'
  return <p>Private</p>
}

export default async function Page() {
  'use cache' // A public cache cannot contain a private one
  return <PrivateSegment />
}
```

## Possible Ways to Fix It

Nest a private cached function only inside another private cached function. You can also call it directly from a component or function that runs during a request. Do not place it inside a public cached function, `unstable_cache()`, or a build-time context.

```jsx filename="app/page.js" highlight={7}
async function PrivateSegment() {
  'use cache: private'
  return <p>Private</p>
}

export default async function Page() {
  // No surrounding "use cache". The private segment runs per request.
  return <PrivateSegment />
}
```

If the data is the same for every user, use the `use cache` directive so Next.js can prerender and reuse the result. If you need per-user data, read it during the request instead of in `generateStaticParams`.

## Useful Links

- [`use cache: private` directive](/docs/app/api-reference/directives/use-cache-private)
- [`use cache` directive](/docs/app/api-reference/directives/use-cache)