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Tutorial - React SPA with an API

This tutorial takes you through the steps needed to adapt a Vite project to use the Cloudflare Vite plugin. Much of the content can also be applied to adapting existing Vite projects and to front-end frameworks other than React.

Introduction

In this tutorial, you will create a React SPA that can be deployed as a Worker with static assets. You will then add an API Worker that can be accessed from the front-end code. You will develop, build, and preview the application using Vite before finally deploying to Cloudflare.

Set up and configure the React SPA

Scaffold a Vite project

Start by creating a React TypeScript project with Vite.

Terminal window
npm create vite@latest -- cloudflare-vite-tutorial --template react-ts

Next, open the cloudflare-vite-tutorial directory in your editor of choice.

Add the Cloudflare dependencies

Terminal window
npm i -D @cloudflare/vite-plugin wrangler

Add the plugin to your Vite config

vite.config.ts
import { defineConfig } from "vite";
import react from "@vitejs/plugin-react";
import { cloudflare } from "@cloudflare/vite-plugin";


export default defineConfig({
  plugins: [react(), cloudflare()],
});

The Cloudflare Vite plugin doesn't require any configuration by default and will look for a wrangler.jsonc, wrangler.json or wrangler.toml in the root of your application.

Refer to the API reference for configuration options.

Create your Worker config file

{
  "name": "cloudflare-vite-tutorial",
  "compatibility_date": "2025-04-03",
  "assets": {
    "not_found_handling": "single-page-application"
  }
}

The not_found_handling value has been set to single-page-application. This means that all not found requests will serve the index.html file. With the Cloudflare plugin, the assets routing configuration is used in place of Vite's default behavior. This ensures that your application's routing configuration works the same way while developing as it does when deployed to production.

Note that the directory field is not used when configuring assets with Vite. The directory in the output configuration will automatically point to the client build output. See Static Assets for more information.

Update the .gitignore file

When developing Workers, additional files are used and/or generated that should not be stored in git. Add the following lines to your .gitignore file:

.gitignore
.wrangler
.dev.vars*

Run the development server

Run npm run dev to start the Vite development server and verify that your application is working as expected.

For a purely front-end application, you could now build (npm run build), preview (npm run preview), and deploy (npm exec wrangler deploy) your application. This tutorial, however, will show you how to go a step further and add an API Worker.

Add an API Worker

Configure TypeScript for your Worker code

Terminal window
npm i -D @cloudflare/workers-types
tsconfig.worker.json
{
  "extends": "./tsconfig.node.json",
  "compilerOptions": {
    "tsBuildInfoFile": "./node_modules/.tmp/tsconfig.worker.tsbuildinfo",
    "types": ["@cloudflare/workers-types/2023-07-01", "vite/client"],
  },
  "include": ["worker"],
}
tsconfig.json
{
  "files": [],
  "references": [
    { "path": "./tsconfig.app.json" },
    { "path": "./tsconfig.node.json" },
    { "path": "./tsconfig.worker.json" },
  ],
}

Add to your Worker configuration

{
  "name": "cloudflare-vite-tutorial",
  "compatibility_date": "2025-04-03",
  "assets": {
    "not_found_handling": "single-page-application"
  },
  "main": "./worker/index.ts"
}

The main field specifies the entry file for your Worker code.

Add your API Worker

worker/index.ts
interface Env {
  ASSETS: Fetcher;
}


export default {
  fetch(request, env) {
    const url = new URL(request.url);


    if (url.pathname.startsWith("/api/")) {
      return Response.json({
        name: "Cloudflare",
      });
    }


    return new Response(null, { status: 404 });
  },
} satisfies ExportedHandler<Env>;

The Worker above will be invoked for any non-navigation request that does not match a static asset. It returns a JSON response if the pathname starts with /api/ and otherwise return a 404 response.

Call the API from the client

Edit src/App.tsx so that it includes an additional button that calls the API and sets some state:

src/App.tsx
import { useState } from "react";
import reactLogo from "./assets/react.svg";
import viteLogo from "/vite.svg";
import "./App.css";


function App() {
  const [count, setCount] = useState(0);
  const [name, setName] = useState("unknown");


  return (
    <>
16 collapsed lines
      <div>
        <a href="https://vite.dev" target="_blank">
          <img src={viteLogo} className="logo" alt="Vite logo" />
        </a>
        <a href="https://react.dev" target="_blank">
          <img src={reactLogo} className="logo react" alt="React logo" />
        </a>
      </div>
      <h1>Vite + React</h1>
      <div className="card">
        <button
          onClick={() => setCount((count) => count + 1)}
          aria-label="increment"
        >
          count is {count}
        </button>
        <p>
          Edit <code>src/App.tsx</code> and save to test HMR
        </p>
      </div>
      <div className="card">
        <button
          onClick={() => {
            fetch("/api/")
              .then((res) => res.json() as Promise<{ name: string }>)
              .then((data) => setName(data.name));
          }}
          aria-label="get name"
        >
          Name from API is: {name}
        </button>
        <p>
          Edit <code>api/index.ts</code> to change the name
        </p>
      </div>
      <p className="read-the-docs">
        Click on the Vite and React logos to learn more
      </p>
    </>
  );
}


export default App;

Now, if you click the button, it will display 'Name from API is: Cloudflare'.

Increment the counter to update the application state in the browser. Next, edit api/index.ts by changing the name it returns to 'Cloudflare Workers'. If you click the button again, it will display the new name while preserving the previously set counter value.

With Vite and the Cloudflare plugin, you can iterate on the client and server parts of your app together, without losing UI state between edits.

Build your application

Run npm run build to build your application.

Terminal window
npm run build

If you inspect the dist directory, you will see that it contains two subdirectories:

  • client - the client code that runs in the browser
  • cloudflare-vite-tutorial - the Worker code alongside the output wrangler.json configuration file

Preview your application

Run npm run preview to validate that your application runs as expected.

Terminal window
npm run preview

This command will run your build output locally in the Workers runtime, closely matching its behaviour in production.

Deploy to Cloudflare

Run npm exec wrangler deploy to deploy your application to Cloudflare.

Terminal window
npm exec wrangler deploy

This command will automatically use the output wrangler.json that was included in the build output.

Next steps

In this tutorial, we created an SPA that could be deployed as a Worker with static assets. We then added an API Worker that could be accessed from the front-end code. Finally, we deployed both the client and server-side parts of the application to Cloudflare.

Possible next steps include:

  • Adding a binding to another Cloudflare service such as a KV namespace or D1 database
  • Expanding the API to include additional routes
  • Using a library, such as Hono ↗ or tRPC ↗, in your API Worker