# @astrojs/deno 🦖
This adapter allows Astro to deploy your SSR site to Deno targets.
Learn how to deploy your Astro site in our [Deno Deploy deployment guide](https://docs.astro.build/en/guides/deploy/deno/).
- [Why Astro Deno](#why-astro-deno)
- [Installation](#installation)
- [Usage](#usage)
- [Configuration](#configuration)
- [Examples](#examples)
- [Troubleshooting](#troubleshooting)
- [Contributing](#contributing)
- [Changelog](#changelog)
## Why Astro Deno
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
Add the Deno adapter to enable SSR in your Astro project with the following `astro add` command. This will install the adapter and make the appropriate changes to your `astro.config.mjs` file in one step.
```sh
# Using NPM
npx astro add deno
# Using Yarn
yarn astro add deno
# Using PNPM
pnpm astro add deno
```
If you prefer to install the adapter manually instead, complete the following two steps:
1. Install the Deno adapter to your project’s dependencies using your preferred package manager. If you’re using npm or aren’t sure, run this in the terminal:
```bash
npm install @astrojs/deno
```
1. Update your `astro.config.mjs` project configuration file with the changes below.
```js ins={3,6-7}
// astro.config.mjs
import { defineConfig } from 'astro/config';
import deno from '@astrojs/deno';
export default defineConfig({
output: 'server',
adapter: deno(),
});
```
Next, Update your `preview` script in `package.json` with the change below.
```json del={8} ins={9}
// package.json
{
// ...
"scripts": {
"dev": "astro dev",
"start": "astro dev",
"build": "astro build",
"preview": "astro preview"
"preview": "deno run --allow-net --allow-read --allow-env ./dist/server/entry.mjs"
}
}
```
You can now use this command to preview your production Astro site locally with Deno.
```bash
npm run preview
```
## Usage
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:
```js
import './dist/entry.mjs';
```
See the `start` option below for how you can have more control over starting the Astro server.
You can also run the script directly using deno:
```sh
deno run --allow-net --allow-read --allow-env ./dist/server/entry.mjs
```
## Configuration
To configure this adapter, pass an object to the `deno()` function call in `astro.config.mjs`.
__`astro.config.mjs`__
```js
import { defineConfig } from 'astro/config';
import deno from '@astrojs/deno';
export default defineConfig({
output: 'server',
adapter: deno({
//options go here
})
});
```
### start
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({
output: 'server',
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);
});
```
### port and hostname
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({
output: 'server',
adapter: deno({
port: 8081,
hostname: 'myhost'
})
});
```
## 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.
## Troubleshooting
For help, check out the `#support-threads` channel on [Discord](https://astro.build/chat). Our friendly Support Squad members are here to help!
You can also check our [Astro Integration Documentation][astro-integration] for more on integrations.
## Contributing
This package is maintained by Astro's Core team. You're welcome to submit an issue or PR!
## Changelog
See [CHANGELOG.md](CHANGELOG.md) for a history of changes to this integration.
[astro-integration]: https://docs.astro.build/en/guides/integrations-guide/