---
description: Extend the default page extensions used by Next.js when resolving pages in the pages directory.
---

# Custom Page Extensions

You can extend the default Page extensions (`.tsx`, `.ts`, `.jsx`, `.js`) used by Next.js. Inside `next.config.js`, add the `pageExtensions` config:

```js
module.exports = {
  pageExtensions: ['mdx', 'md', 'jsx', 'js', 'tsx', 'ts'],
}
```

Changing these values affects _all_ Next.js pages, including the following:

- `middleware.js`
- `pages/_document.js`
- `pages/_app.js`
- `pages/api/`

For example, if you reconfigure `.ts` page extensions to `.page.ts`, you would need to rename pages like `_app.page.ts`.

## Including non-page files in the `pages` directory

You can colocate test files or other files used by components in the `pages` directory. Inside `next.config.js`, add the `pageExtensions` config:

```js
module.exports = {
  pageExtensions: ['page.tsx', 'page.ts', 'page.jsx', 'page.js'],
}
```

Then, rename your pages to have a file extension that includes `.page` (e.g. rename `MyPage.tsx` to `MyPage.page.tsx`). Ensure you rename _all_ Next.js pages, including the files mentioned above.

## Related

<div class="card">
  <a href="/docs/api-reference/next.config.js/introduction.md">
    <b>Introduction to next.config.js:</b>
    <small>Learn more about the configuration file used by Next.js.</small>
  </a>
</div>