> ## Documentation Index
> Fetch the complete documentation index at: https://aerojs.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.
# Metadata
> Configure your site URL, manage head tags, and set up SEO basics for your Aero site.
Metadata covers everything that goes in `` and anything that helps search engines and social platforms understand your site — titles, descriptions, canonical URLs, Open Graph tags, and sitemaps.
## Site URL
Set your canonical site URL in the Aero config. This powers sitemaps, canonical links, and `import.meta.env.SITE`:
```ts aero.config.ts theme={"theme":"github-dark-default"}
import { defineConfig } from '@aero-js/core/config'
export default defineConfig({
site: { url: 'https://example.com' },
})
```
```ts vite.config.ts theme={"theme":"github-dark-default"}
import { defineConfig } from 'vite'
import { aero } from '@aero-js/core/vite'
export default defineConfig({
plugins: [
aero({ site: { url: 'https://example.com' } }),
],
})
```
Once set, the URL is available in two places:
| Context | Access |
| --------------------------- | ---------------------- |
| Build scripts and templates | `Aero.site.url` |
| Client scripts | `import.meta.env.SITE` |
## Head tags in layouts
Manage `` content in your base layout. Use props to let pages customize their title and description:
```html client/layouts/base.html theme={"theme":"github-dark-default"}
{ title }
```
Pages pass metadata as props through the layout:
```html client/pages/about.html theme={"theme":"github-dark-default"}
About
```
## Sitemap
When `site.url` is set, Aero automatically generates `sitemap.xml` in `dist/` during a static build. It includes all pre-rendered routes as absolute URLs and excludes the 404 page.
Link to it from your layout's ``:
```html theme={"theme":"github-dark-default"}
```
## robots.txt
Place a `robots.txt` in the `public/` directory. It is copied to `dist/` unchanged:
```
User-agent: *
Allow: /
Sitemap: https://example.com/sitemap.xml
```
## Favicon
Place favicon files in `public/` and reference them in your layout's ``:
```html theme={"theme":"github-dark-default"}
```