---
title: Cloudflare Workers - Dart Edge
description: Write and deploy Dart to the Cloudflare Workers network.
---

# Cloudflare Workers

[Cloudflare Workers](https://workers.cloudflare.com/) enable you to deploy serverless code across the globe.
The Workers platform also comes with additional runtime APIs, such as [Durable Objects](https://developers.cloudflare.com/workers/runtime-apis/durable-objects/) & [KV](https://developers.cloudflare.com/workers/runtime-apis/kv/) that allow you to build powerful applications. See [the API documentation](/platform/cloudflare/apis) for more information.

## Getting Started

Before getting started, you need to install the Cloudflare [`wrangler` CLI](https://developers.cloudflare.com/workers/wrangler/) globally.

Next, either use the `edge` CLI command or setup manually:

<Tabs
  values={[
    { label: 'Edge CLI', value: 'cli' },
    { label: 'Manually', value: 'manually' },
  ]}
>
  <TabItem value="cli">
    Create a new project using the `edge` CLI command:

    ```sh
    edge new cloudflare_workers new_project
    ```

    This command will create a new barebones template in the current directory. Once complete, install the dependencies:

    ```
    dart pub get
    ```

  </TabItem>
  <TabItem value="manually">
    Install the `cloudflare_workers` package:

    ```bash
    dart pub add cloudflare_workers
    ```

    Next, create a `wrangler.toml` file at the root of your project with the following configuration:

    ```toml
    name = "cloudflare_workers_example"
    compatibility_date = "2022-11-30"
    main = ".dart_tool/edge/entry.js"

    [build]
    command = "dart run edge build cloudflare_workers --dev"
    watch_dir = ["lib"]
    ```

    Next create a `lib/main.dart` file, import the `cloudflare_workers` package and setup a `fetch` handler, to handle incoming HTTP requests:

    ```dart
    import 'package:cloudflare_workers/cloudflare_workers.dart';

    void main() {
      CloudflareWorkers(fetch: (request, env, ctx) {
        return Response("Hello from Vercel Edge!");
      });
    }
    ```

    Add the `.dart_tool` directory to your `.gitignore` file.

  </TabItem>
</Tabs>

Open the `lib/main.dart` file to view the minimal HTTP request fetch handler.

Each incoming request to your edge function will be passed to the `fetch` handler, which is expected to return a `Response` instance. The `fetch` handler provides a `Request` instance which contains useful information about the incoming request, such as the method, URL, headers, body and more.

Alongside the `Request` instance, you are also provided an `Environment` instance, enables you to access service bindings (e.g. Durable Objects). Additionally the `ExecutionContext` argument enables you to perform actions such as defining functions which can run after a response has been sent to the client.

## Local development

To run your application locally, use the `wrangler dev --local` command from the root of your project:

```bash
wrangler dev --local
```

> You can remove the `--local` flag to run your code directly on the Cloudflare Worker environment. This is useful for testing the production environment locally, however it will take longer to start up as your code is uploaded.

This command will start a development server where you can access your application, by default at `http://127.0.0.1:8787`. Any changes you make to your Dart code will trigger a hot-reload.

## Deployment

To deploy your application to Cloudflare Workers, first remove the `--dev` flag from the `wrangler.toml` file:

```diff
[build]
- command = "dart run edge build cloudflare --dev"
+ command = "dart run edge build cloudflare"
```

Removing the `--dev` flag will ensure that your application is built in production mode, which will result in a smaller bundle size and optimized code.

<Info>
  Please upvote [this feature
  request](https://github.com/cloudflare/wrangler2/issues/2634) to help remove
  this manual step!
</Info>

Next, run the `wrangler publish` command from the root of your project:

```bash
wrangler publish
```