Routing

Astro uses file-based routing to generate your build URLs based on the file layout of your project src/pages directory. When a file is added to the src/pages directory of your project, it is automatically available as a route based on its filename.

Static routes

Astro Components (.astro) and Markdown Files (.md) in the src/pages directory become pages on your website. Each page’s route is decided based on its filename and path within the src/pages directory. This means that there is no separate “routing config” to maintain in an Astro project.

# Example: Static routes
src/pages/index.astro        -> mysite.com/
src/pages/about.astro        -> mysite.com/about
src/pages/about/index.astro  -> mysite.com/about
src/pages/about/me.astro     -> mysite.com/about/me
src/pages/posts/1.md         -> mysite.com/posts/1

Dynamic routes

Sometimes, you need to generate many URLs from a single page component. Astro uses file-based routing to support dynamic route parameters in the filename, so that one page can match many dynamic routes based on some pattern.

An important thing to keep in mind: Astro is a static site builder. There is no Astro server to run in production, which means that every page must be built ahead of time. Pages that use dynamic routes must export a getStaticPaths() function which will tell Astro exactly what pages to generate. Learn more by viewing the complete API Reference.

Named parameters

Dynamic parameters are encoded into the filename using [bracket] notation:

  • pages/blog/[slug].astro/blog/:slug (/blog/hello-world, /blog/post-2, etc.)
  • pages/[username]/settings.astro → (/fred/settings, /drew/settings, etc.)
  • pages/[lang]-[version]/info.astro → (/en-v1/info, /fr-v2/info, etc.)

Example: Named parameters

Consider the following page pages/post/[pid].astro:

---
// Example: src/pages/post/[pid].astro
const {pid} = Astro.request.params;
---
<p>Post: {pid}</p>

Any route like /post/1, /post/abc, etc. will be matched by pages/post/[pid].astro. The matched path parameter will be passed to the page component at Astro.request.params.

For example, the route /post/abc will have the following Astro.request.params object available:

{ "pid": "abc" }

Multiple dynamic route segments can be combined to work the same way. The page pages/post/[pid]/[comment].astro will match the route /post/abc/a-comment and its query object will be:

{ "pid": "abc", "comment": "a-comment" }

Rest parameters

If you need more flexibility in your URL routing, you can use a rest parameter as a universal catch-all. You do this by adding three dots (...) inside your brackets. For example:

  • pages/post/[...slug].astro → (/post/a, /post/a/b, /post/a/b/c, etc.)

Matched parameters will be sent as a query parameter (slug in the example) to the page. In the example above, the path /post/a/b/c will have the following query object:

{ "slug": "a/b/c" }

You can use names other than slug, such as: [...param] or [...name].

Rest parameters are optional by default, so pages/post/[...slug].astro could match /post/ as well.

Example: Rest parameters

For a real-world example, you might implement GitHub’s file viewer like so:

/[org]/[repo]/tree/[branch]/[...file]

In this example, a request for /snowpackjs/astro/tree/main/docs/public/favicon.svg would result in the following parameters being available to the page:

{
	org: 'snowpackjs',
	repo: 'astro',
	branch: 'main',
	file: 'docs/public/favicon.svg'
}

Caveats

  • Static routes without path params will take precedence over all other routes, and named path params over catch all path params. Take a look at the following examples:
    • pages/post/create.astro - Will match /post/create
    • pages/post/[pid].astro - Will match /post/1, /post/abc, etc. But not /post/create
    • pages/post/[...slug].astro - Will match /post/1/2, /post/a/b/c, etc. But not /post/create, /post/abc