basePath

To deploy a Next.js application under a sub-path of a domain you can use the basePath config option.

basePath allows you to set a path prefix for the application. For example, to use /docs instead of '' (an empty string, the default), open next.config.js and add the basePath config:

module.exports = {
  basePath: '/docs',
}

Good to know: This value must be set at build time and cannot be changed without re-building as the value is inlined in the client-side bundles.

Links

When linking to other pages using next/link and next/router the basePath will be automatically applied.

For example, using /about will automatically become /docs/about when basePath is set to /docs.

export default function HomePage() {
  return (
    <>
      <Link href="/about">About Page</Link>
    </>
  )
}

Output html:

<a href="/docs/about">About Page</a>

This makes sure that you don't have to change all links in your application when changing the basePath value.

Images

When using the next/image component, you will need to add the basePath in front of src.

For example, using /docs/me.png will properly serve your image when basePath is set to /docs.

import Image from 'next/image'

function Home() {
  return (
    <>
      <h1>My Homepage</h1>
      <Image
        src="/docs/me.png"
        alt="Picture of the author"
        width={500}
        height={500}
      />
      <p>Welcome to my homepage!</p>
    </>
  )
}

export default Home