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

# Vercel Edge

The [Vercel Edge Network](https://vercel.com/features/edge-functions) network is a popular platform for deploying serverless Edge functions. Alongside the performant runtime environment, your code can be easily deployed and managed through your own Vercel account, providing access to preview builds, environment customization, and more.

## Getting Started

Before getting started, you need to install the [`vercel` CLI](https://vercel.com/docs/cli) 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 vercel_edge 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 `vercel_edge` package:

    ```bash
    dart pub add vercel_edge
    ```

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

    ```json
    {
      "buildCommand": "dart run edge build vercel_edge",
      "devCommand": "dart run edge build vercel_edge --dev"
    }
    ```

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

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

    void main() {
      VercelEdge(fetch: (request) {
        return Response("Hello from Vercel Edge!");
      });
    }
    ```

    Add the `.vercel` & `.dart_tool` directories to your `.gitignore` file.

  </TabItem>
</Tabs>

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

```dart
void main() {
  VercelEdge(fetch: (request) {
    return Response("Hello World!");
  });
}
```

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.

## Local development

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

```bash
vercel dev
# or vc dev
```

> If this is your first time running the command, you'll be prompted to login to your Vercel account and choose (or create) a project to link to.

This command will start a development server where you can access your application, by default at `http://localhost:3000`. Any changes you make to your Dart code will trigger a hot-reload.

You can change what port the application runs on by providing the `--listen 3001` argument to the dev command.

## Deployment

To deploy your application to Vercel, first build your application running the following command from the root of your project:

```sh
vercel build
```

Once built, you can deploy using the `deploy` command:

```sh
vercel deploy --prebuilt
```

The `--prebuilt` flag tells Vercel to skip the build step, as we've already built the application (since Vercel cannot compile Dart on their servers). We'll likely create a GitHub action to handle this process automatically in the future.