pageExtensions

By default, Next.js accepts files with the following extensions: .tsx, .ts, .jsx, .js. This can be modified to allow other extensions like markdown (.md, .mdx).

const withMDX = require('@next/mdx')()

/** @type {import('next').NextConfig} */
const nextConfig = {
  pageExtensions: ['js', 'jsx', 'ts', 'tsx', 'md', 'mdx'],
}

module.exports = withMDX(nextConfig)

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

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

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

• middleware.js
• instrumentation.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 middleware.page.ts, instrumentation.page.ts, _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:

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.