--- title: notFound description: API Reference for the notFound function. --- The `notFound` function allows you to render the [`not-found file`](/docs/app/api-reference/file-conventions/not-found) within a route segment as well as inject a `` tag. ## `notFound()` Invoking the `notFound()` function throws a `NEXT_HTTP_ERROR_FALLBACK;404` error and terminates rendering of the route segment in which it was thrown. Specifying a [**not-found** file](/docs/app/api-reference/file-conventions/not-found) allows you to gracefully handle such errors by rendering a Not Found UI within the segment. ```jsx filename="app/user/[id]/page.js" import { notFound } from 'next/navigation' async function fetchUser(id) { const res = await fetch('https://...') if (!res.ok) return undefined return res.json() } export default async function Profile({ params }) { const { id } = await params const user = await fetchUser(id) if (!user) { notFound() } // ... } ``` > **Good to know**: `notFound()` does not require you to use `return notFound()` due to using the TypeScript [`never`](https://www.typescriptlang.org/docs/handbook/2/functions.html#never) type. ## Version History | Version | Changes | | --------- | ---------------------- | | `v13.0.0` | `notFound` introduced. |