Dynamic Routes

When you don't know the exact segment names ahead of time and want to create routes from dynamic data, you can use Dynamic Segments that are filled in at request time or prerendered at build time.

Convention

A Dynamic Segment can be created by wrapping a folder's name in square brackets: [folderName]. For example, [id] or [slug].

Dynamic Segments can be access from useRouter.

Example

For example, a blog could include the following route pages/blog/[slug].js where [slug] is the Dynamic Segment for blog posts.

import { useRouter } from 'next/router';
 
export default function Page() {
  const router = useRouter();
  return <p>Post: {router.query.slug}</p>;
}

Catch-all Segments

Dynamic Segments can be extended to catch-all subsequent segments by adding an ellipsis inside the brackets [...folderName].

For example, pages/shop/[...slug].js will match /shop/clothes, but also /shop/clothes/tops, /shop/clothes/tops/t-shirts, and so on.

Optional Catch-all Segments

Catch-all Segments can be made optional by including the parameter in double square brackets: [[...folderName]].

For example, pages/shop/[[...slug]].js will also match /shop, in addition to /shop/clothes, /shop/clothes/tops, /shop/clothes/tops/t-shirts.

The difference between catch-all and optional catch-all segments is that with optional, the route without the parameter is also matched (/shop in the example above).