# Not found

URL: /code/file-conventions/not-found · Id: `page:code/file-conventions/not-found`

> A not-found file answers every unmatched path in its folder and below.

A `not-found.mdx` file answers every unmatched path in its folder and below, with status 404.

```text
sites/www/
├── not-found.mdx          every unmatched path
└── blog/not-found.mdx     unmatched paths under /blog
```

## Reference
MDX, like a [Page](/business/nouns/page), with no frontmatter keys of its own. The nearest file up the tree answers.

## Examples
### Minimal
```mdx title="sites/www/not-found.mdx"
That page does not exist.
```

### Leaseline
```mdx title="sites/www/not-found.mdx"
That page moved or never existed.

<CallToAction heading="See pricing" action="/pricing" />
```

## What it builds
The [SiteBuilder](/code/builders/site) compiles it into the 404 Page for its subtree.

- a `Page` of kind `not-found`, served with status 404 and its Markdown twin
- a [Metric](/business/nouns/metric) count of misses by path, so a broken link shows on the [Site](/business/nouns/site)'s [Dashboard](/business/nouns/dashboard)

## Good to know
- Every Site has a generated one until a file overrides it.