SvelteKit

Svelte ↗ is an increasingly popular, open-source framework for building user interfaces and web applications. Unlike most frameworks, Svelte is primarily a compiler that converts your component code into efficient JavaScript that surgically updates the DOM when your application state changes.

In this guide, you will create a new Svelte application and deploy it using Cloudflare Pages. You will use SvelteKit ↗, the official Svelte framework for building web applications of all sizes.

Setting up a new project

Use the create-cloudflare ↗ CLI (C3) to set up a new project. C3 will create a new project directory, initiate Svelte’s official setup tool, and provide the option to deploy instantly.

To use create-cloudflare to create a new Svelte project, run the following command:

npm

npm create cloudflare@latest -- my-svelte-app --framework=svelte

yarn

yarn create cloudflare@latest my-svelte-app --framework=svelte

pnpm

pnpm create cloudflare@latest my-svelte-app --framework=svelte

SvelteKit will prompt you for customization choices. For the template option, choose one of the application/project options. The remaining answers will not affect the rest of this guide. Choose the options that suit your project.

create-cloudflare will then install dependencies, including the Wrangler CLI and the @sveltejs/adapter-cloudflare adapter, and ask you setup questions.

After you have installed your project dependencies, start your application:

npm run dev

Before you continue

All of the framework guides assume you already have a fundamental understanding of Git ↗. If you are new to Git, refer to this summarized Git handbook ↗ on how to set up Git on your local machine.

If you clone with SSH, you must generate SSH keys ↗ on each computer you use to push or pull from GitHub.

Refer to the GitHub documentation ↗ and Git documentation ↗ for more information.

Create a GitHub repository

Create a new GitHub repository by visiting repo.new ↗. After creating a new repository, go to your newly created project directory to prepare and push your local application to GitHub by running the following commands in your terminal:

git init
git remote add origin https://github.com/<your-gh-username>/<repository-name>
git add .
git commit -m "Initial commit"
git branch -M main
git push -u origin main

SvelteKit Cloudflare configuration

To use SvelteKit with Cloudflare Pages, you need to add the Cloudflare adapter ↗ to your application.

Note

If using create-cloudflare (C3) ↗, you can bypass adding an adapter as C3 automatically installs any necessary adapters and configures them when creating your project.

1. Install the Cloudflare Adapter by running npm i --save-dev @sveltejs/adapter-cloudflare in your terminal.
2. Include the adapter in svelte.config.js:

 import adapter from '@sveltejs/adapter-auto';
 import adapter from '@sveltejs/adapter-cloudflare';

/** @type {import('@sveltejs/kit').Config} */
const config = {
  kit: {
    adapter: adapter(),
    // ... truncated ...
  }
};

export default config;

3. (Needed if you are using TypeScript) Include support for environment variables. The env object, containing KV namespaces and other storage objects, is passed to SvelteKit via the platform property along with context and caches, meaning you can access it in hooks and endpoints. For example:

declare namespace App {
    interface Locals {}

   interface Platform {
       env: {
           COUNTER: DurableObjectNamespace;
       };
       context: {
           waitUntil(promise: Promise<any>): void;
       };
       caches: CacheStorage & { default: Cache }
   }

    interface Session {}

    interface Stuff {}
}

4. Access the added KV or Durable objects (or generally any binding) in your endpoint with env:

export async function post(context) {
  const counter = context.platform.env.COUNTER.idFromName("A");
}

Note

In addition to the Cloudflare adapter, review other adapters you can use in your project:

• @sveltejs/adapter-auto ↗

  SvelteKit’s default adapter automatically chooses the adapter for your current environment. If you use this adapter, no configuration is needed ↗. However, the default adapter introduces a few disadvantages for local development because it has no way of knowing what platform the application is going to be deployed to.

To solve this issue, provide a CF_PAGES variable to SvelteKit so that the adapter can detect the Pages platform. For example, when locally building the application: CF_PAGES=1 vite build.

• @sveltejs/adapter-static ↗ Only produces client-side static assets (no server-side rendering) and is compatible with Cloudflare Pages. Review the official SvelteKit documentation ↗ for instructions on how to set up the adapter. Keep in mind that if you decide to use this adapter, the build directory, instead of .svelte-kit/cloudflare, becomes build. You must also configure your Cloudflare Pages application’s build directory accordingly.

Warning

If you are using any adapter different from the default SvelteKit adapter, remember to commit and push your adapter setting changes to your GitHub repository before attempting the deployment.

Deploy with Cloudflare Pages

Deploy via the create-cloudflare CLI (C3)

If you use create-cloudflare(C3) ↗ to create your new Svelte project, C3 will install all dependencies needed for your project and prompt you to deploy your project via the CLI. If you deploy, your site will be live and you will be provided with a deployment URL.

Deploy via the Cloudflare dashboard

1. Log in to the Cloudflare dashboard ↗ and select your account.
2. In Account Home, select Workers & Pages > Create application > Pages > Connect to Git.

You will be asked to authorize access to your GitHub account if you have not already done so. Cloudflare needs this authorization to deploy your projects from your GitHub account. You may narrow Cloudflare’s access to specific repositories. However, you will have to manually update this list within your GitHub settings ↗ when you want to add more repositories to Cloudflare Pages.

Select the new GitHub repository that you created and, in Set up builds and deployments, provide the following information:

Configuration option	Value
Production branch	main
Build command	npm run build
Build directory	.svelte-kit/cloudflare

Optionally, you can customize the Project name field. It defaults to the GitHub repository’s name, but it does not need to match. The Project name value is assigned as your *.pages.dev subdomain.

After completing configuration, click the Save and Deploy button.

You will see your first deploy pipeline in progress. Pages installs all dependencies and builds the project as specified.

Cloudflare Pages will automatically rebuild your project and deploy it on every new pushed commit.

Additionally, you will have access to preview deployments, which repeat the build-and-deploy process for pull requests. With these, you can preview changes to your project with a real URL before deploying them to production.

Note

For the complete guide to deploying your first site to Cloudflare Pages, refer to the Get started guide.

Functions setup

In SvelteKit, functions are written as endpoints. Functions contained in the /functions directory at the project’s root will not be included in the deployment, which compiles to a single _worker.js file.

To have the functionality equivalent to Pages Functions onRequests, you need to write standard request handlers in SvelteKit. For example, the following TypeScript file behaves like an onRequestGet:

import type { RequestHandler } from "./$types";

export const GET = (({ url }) => {
  return new Response(String(Math.random()));
}) satisfies RequestHandler;

SvelteKit API Routes

For more information about SvelteKit API Routes, refer to the SvelteKit documentation ↗.

Learn more

By completing this guide, you have successfully deployed your Svelte site to Cloudflare Pages. To get started with other frameworks, refer to the list of Framework guides.