Lesson 1.16mIntermediate18.2k studentsFree preview

File-system routing and the app directory

The App Router maps folders to URL segments and reserved filenames to behaviour. Once you can read a folder tree as a set of routes, most of the framework stops being magic.

This lesson sits in Routing and Layouts, part of Next.js App Router in Depth. It assumes what came before it and leads directly into the next lesson in the module.

In this lesson you will

  • Map folders and page files to URL segments
  • Use route groups to organise without affecting the URL
  • Recognise the reserved files: page, layout, loading, error, not-found

Pro tip

A folder in parentheses is a route group: it organises your files without adding a segment to the URL.

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