# Develop locally

## Develop JavaScript App locally

It is possible to develop your JavaScript code locally and test it in your app. To do this you need to have a development environment featuring an HTTP server.

We recommend using a build/development tool like [Vite](https://vitejs.dev/), it is an easy to use development environment for all kinds of frameworks. It offers support to easily create PWAs, and more. It is not required to use [Vite](https://vitejs.dev/), you can also use your own setup that hosts a development HTTP server.

### 1. Start your Dev Server[​](http://localhost:3000/guides/develop-js-app-locally#1-start-your-dev-server) <a href="#id-1-start-your-dev-server" id="id-1-start-your-dev-server"></a>

* **Start your development server**, for example, when using Vite run:

```
npm run dev
```

### 2. Copy the local server URL[​](http://localhost:3000/guides/develop-js-app-locally#2-copy-the-local-server-url) <a href="#id-2-copy-the-local-server-url" id="id-2-copy-the-local-server-url"></a>

* **Copy the URL** of your server. Vite uses as default: `http://localhost:3000`

![](http://localhost:3000/assets/images/local-development-terminal-start-974103c5d22d6866bf2a78620e46348b.png)

### 3. Setup your app[​](http://localhost:3000/guides/develop-js-app-locally#3-setup-your-app) <a href="#id-3-setup-your-app" id="id-3-setup-your-app"></a>

* Open your app in the designer and **open the JavaScript block**.
* **Enable Development Mode** by ticking the checkbox in the right side panel.
* Enter the **Development URL**.
* **Save** your changes.
* Click on the JavaScript block to **reload**.

![](http://localhost:3000/assets/images/local-development-setup-0f1b84c0360a291bfa1ba84244cc5186.gif)

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