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.
[Netlify](https://www.netlify.com/) is a deployment platform that allows you to host your site by connecting directly to your GitHub repository. This adapter enhances the Astro build process to prepare your project for deployment through Netlify.
Add the Netlify 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.
1. Install the Netlify 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:
Netlify has two serverless platforms, Netlify Functions and [Netlify's experimental Edge Functions](https://docs.netlify.com/netlify-labs/experimental-features/edge-functions/#app). With Edge Functions your code is distributed closer to your users, lowering latency.
The Netlify adapter builds to a single function by default. Astro 2.7 added support for splitting your build into separate entry points per page. If you use this configuration, the Netlify adapter will generate a separate function for each page. This can help reduce the size of each function so they are only bundling code used on that page.
For static sites you usually don't need an adapter. However, if you use `redirects` configuration (experimental) in your Astro config, the Netlify adapter can be used to translate this to the proper `_redirects` format.
> You can still include a `public/_redirects` file for manual redirects. Any redirects you specify in the redirects config are appended to the end of your own.
After [performing a build](https://docs.astro.build/en/guides/deploy/#building-your-site-locally) the `netlify/` folder will contain [Netlify Functions](https://docs.netlify.com/functions/overview/) in the `netlify/functions/` folder.
The [Netlify Blog post on Astro](https://www.netlify.com/blog/how-to-deploy-astro/) and the [Netlify Documentation](https://docs.netlify.com/integrations/frameworks/astro/) provide more information on how to use this integration to deploy to Netlify.
[Netlify On-demand Builders](https://docs.netlify.com/configure-builds/on-demand-builders/) are serverless functions used to build and cache page content on Netlify’s Edge CDN. You can enable these functions with the `builders` option:
Netlify Functions requires binary data in the `body` to be base64 encoded. The `@astrojs/netlify/functions` adapter handles this automatically based on the `Content-Type` header.
We check for common mime types for audio, image, and video files. To include specific mime types that should be treated as binary data, include the `binaryMediaTypes` option with a list of binary mime types.
- The [Astro Netlify Edge Starter](https://github.com/sarahetter/astro-netlify-edge-starter) provides an example and a guide in the README.
- [Browse Astro Netlify projects on GitHub](https://github.com/search?q=%22%40astrojs%2Fnetlify%22+filename%3Apackage.json&type=Code) for more examples!