An SSR adapter for use with Cloudflare Pages Functions targets. Write your code in Astro/Javascript and deploy to Cloudflare Pages.

Add the Cloudflare 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.

# Using NPM
npx astro add cloudflare
# Using Yarn
yarn astro add cloudflare
# Using PNPM
pnpm astro add cloudflare


If you prefer to install the adapter manually instead, complete the following two steps:

  1. Add the Cloudflare 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:
npm install @astrojs/cloudflare


  1. Add the following to your astro.config.mjs file:
import { defineConfig } from 'astro/config';
import cloudflare from '@astrojs/cloudflare';

export default defineConfig({
  output: 'server',
  adapter: cloudflare()


mode: "advanced" | "directory"

default "advanced"

Cloudflare Pages has 2 different modes for deploying functions, advanced mode which picks up the _worker.js in dist, or a directory mode where pages will compile the worker out of a functions folder in the project root.

For most projects the adapter default of advanced will be sufficient; the dist folder will contain your compiled project. Switching to directory mode allows you to use pages plugins such as Sentry or write custom code to enable logging.

In directory mode the adapter will compile the client side part of your app the same way, but moves the worker script into a functions folder in the project root. The adapter will only ever place a [[path]].js in that folder, allowing you to add additional plugins and pages middleware which can be checked into version control. Cloudflare documentation contains more information about writing custom functions.

// directory mode
export default defineConfig({
  adapter: cloudflare({ mode: "directory" }),


In order for preview to work you must install wrangler

$ pnpm install wrangler --save-dev


It’s then possible to update the preview script in your package.json to "preview": "wrangler pages dev ./dist". This will allow you to run your entire application locally with Wrangler, which supports secrets, environment variables, KV namespaces, Durable Objects and all other supported Cloudflare bindings.

Access to the Cloudflare runtime

Section titled Access to the Cloudflare runtime

You can access all the Cloudflare bindings and environment variables from Astro components and API routes through the adapter API.

import { getRuntime } from "@astrojs/cloudflare/runtime";



Depending on your adapter mode (advanced = worker, directory = pages), the runtime object will look a little different due to differences in the Cloudflare API.

See Cloudflare’s documentation for working with environment variables.

export function get({ params }) {
  // Access environment variables per request inside a function
  const serverUrl = import.meta.env.SERVER_URL;
  const result = await fetch(serverUrl + "/user/" + params.id);
  return {
    body: await result.text(),


Headers, Redirects and function invocation routes

Section titled Headers, Redirects and function invocation routes

Cloudflare has support for adding custom headers, configuring static redirects and defining which routes should invoke functions. Cloudflare looks for _headers, _redirects, and _routes.json files in your build output directory to configure these features. This means they should be placed in your Astro project’s public/ directory.

By default, @astrojs/cloudflare will generate a _routes.json file that lists all files from your dist/ folder and redirects from the _redirects file in the exclude array. This will enable Cloudflare to serve files and process static redirects without a function invocation. Creating a custom _routes.json will override this automatic optimization and, if not configured manually, cause function invocations that will count against the request limits of your Cloudflare plan.

For help, check out the #support channel on Discord. Our friendly Support Squad members are here to help!

You can also check our Astro Integration Documentation for more on integrations.

Currently, errors during running your application in Wrangler are not very useful, due to the minification of your code. For better debugging, you can add vite.build.minify = false setting to your astro.config.js

export default defineConfig({
  adapter: cloudflare(),
  output: 'server',

  vite: {
    build: {
      minify: false


This package is maintained by Astro’s Core team. You’re welcome to submit an issue or PR!