If you're using Astro as a static site builder—its behavior out of the box—you don't need an adapter.
If you wish to [use server-side rendering (SSR)](https://docs.astro.build/en/guides/server-side-rendering/), Astro requires an adapter that matches your deployment runtime.
[Deno](https://deno.land/) is a runtime similar to Node, but with an API that's more similar to the browser's API. This adapter provides access to Deno's API and creates a script to run your project on a Deno server.
## Installation
First, install the `@astrojs/deno` package using your package manager. If you're using npm or aren't sure, run this in the terminal:
After [performing a build](https://docs.astro.build/en/guides/deploy/#building-your-site-locally) there will be a `dist/server/entry.mjs` module. You can start a server by importing this module in your Deno app:
This adapter automatically starts a server when it is imported. You can turn this off with the `start` option:
```js
import { defineConfig } from 'astro/config';
import deno from '@astrojs/deno';
export default defineConfig({
adapter: deno({
start: false
})
});
```
If you disable this, you need to write your own Deno web server. Import and call `handle` from the generated entry script to render requests:
```ts
import { serve } from "https://deno.land/std@0.132.0/http/server.ts";
import { handle } from './dist/entry.mjs';
serve((req: Request) => {
// Check the request, maybe do static file handling here.
return handle(req);
});
```
</details>
<details>
<summary><strong>port</strong> and <strong>hostname</strong></summary>
You can set the port (default: `8085`) and hostname (default: `0.0.0.0`) for the deno server to use. If `start` is false, this has no effect; your own server must configure the port and hostname.
```js
import { defineConfig } from 'astro/config';
import deno from '@astrojs/deno';
export default defineConfig({
adapter: deno({
port: 8081,
hostname: 'myhost'
})
});
```
</details>
## Examples
The [Astro Deno](https://github.com/withastro/astro/tree/main/examples/deno) example includes a `preview:deno` command that runs the entry script directly. Run `npm run build` then `npm run preview:deno` to run the production deno server.
