---
title: onDemandEntries
description: Configure how Next.js will dispose and keep in memory pages created in development.
url: "https://nextjs.org/docs/15/app/api-reference/config/next-config-js/onDemandEntries"
version: 15.5.15
lastUpdated: 2025-06-16
prerequisites:
  - "Configuration: /docs/15/app/api-reference/config"
  - "next.config.js: /docs/15/app/api-reference/config/next-config-js"
---


Next.js exposes some options that give you some control over how the server will dispose or keep in memory built pages in development.

To change the defaults, open `next.config.js` and add the `onDemandEntries` config:

```js filename="next.config.js"
module.exports = {
  onDemandEntries: {
    // period (in ms) where the server will keep pages in the buffer
    maxInactiveAge: 25 * 1000,
    // number of pages that should be kept simultaneously without being disposed
    pagesBufferLength: 2,
  },
}
```
---

For an index of all available documentation, see [/docs/15/llms.txt](/docs/15/llms.txt)