> ## Documentation Index
> Fetch the complete documentation index at: https://mintlify.com/medusajs/medusa/llms.txt
> Use this file to discover all available pages before exploring further.

# medusa develop

> Learn how to use the medusa develop command to start a development server.

# medusa develop

Start the Medusa development server with automatic file watching and hot reloading.

## Usage

```bash theme={null}
medusa develop
```

Alias:

```bash theme={null}
medusa dev
```

## Description

The `medusa develop` command starts a development server that watches your file system and automatically restarts or reloads when files change. This is the primary command you'll use during development.

### How It Works

1. Initializes the Medusa container and loads your configuration
2. Forks a child process running `medusa start`
3. Watches your project files for changes
4. Automatically reloads or restarts the server when files change

### File Watching

The development server watches all files in your project except:

* Dot files (files starting with `.`)
* `node_modules/`
* `dist/`
* `static/`
* `private/`
* `src/admin/`
* `.medusa/`

When a file is created, modified, or removed, the development server automatically reloads.

### Hot Module Replacement (HMR)

By default, the development server uses a standard restart approach. If the `backend-hmr` feature flag is enabled, the server will use Hot Module Replacement for faster reloads without a full restart.

With HMR enabled, you'll see:

```bash theme={null}
[HMR] Using backend HMR dev server (reload on file change)
[HMR] Watching filesystem to reload dev server on file change
```

Without HMR:

```bash theme={null}
[Watcher] Using standard dev server (restart on file change)
[Watcher] Watching filesystem to reload dev server on file change
```

## Options

### `--types`

Generate automated types for modules inside the `.medusa` directory.

```bash theme={null}
medusa develop --types
```

* Type: `boolean`
* Default: `true`

### `-H`, `--host`

Set the host for the development server.

```bash theme={null}
medusa develop --host 0.0.0.0
```

* Type: `string`
* Default: Value of `HOST` environment variable, if set

### `-p`, `--port`

Set the port for the development server.

```bash theme={null}
medusa develop --port 8000
```

* Type: `string`
* Default: Value of `PORT` environment variable, or `9000`

## Examples

### Basic Usage

Start the development server on the default port:

```bash theme={null}
medusa develop
```

Output:

```bash theme={null}
[Watcher] Using standard dev server (restart on file change)
info: Processing... 
info: Starting Medusa...
info: Server is ready on port 9000
[Watcher] Watching filesystem to reload dev server on file change
```

### Custom Port and Host

Start the development server on a custom port and host:

```bash theme={null}
medusa develop --host 0.0.0.0 --port 8000
```

### Disable Type Generation

Start the development server without generating types:

```bash theme={null}
medusa develop --no-types
```

### File Change Example

When you modify a file, you'll see output like:

```bash theme={null}
[Watcher] modified src/api/routes.ts modified: restarting dev server
info: Stopping server...
info: Server stopped
info: Starting Medusa...
info: Server is ready on port 9000
[Watcher] Reloaded in 1234.56ms
```

## Environment Variables

The development server sets the following environment variables:

* `NODE_ENV=development` - Automatically set to development mode
* `MEDUSA_HMR_ENABLED=true` - Set when HMR is enabled

## Stopping the Server

To stop the development server, press `Ctrl+C` in your terminal. The first time you stop the server, you'll see a message about starring Medusa on GitHub:

```bash theme={null}
┌─────────────────────────────────────────────────────┐
│                                                     │
│     ✨ Thanks for using Medusa. ✨                  │
│                                                     │
│     If you liked it, please consider starring us   │
│     on GitHub                                       │
│     https://medusajs.com/star                       │
│                                                     │
│     Note: you will not see this message again.     │
│                                                     │
└─────────────────────────────────────────────────────┘
```

## Troubleshooting

### Port Already in Use

If the default port `9000` is already in use, specify a different port:

```bash theme={null}
medusa develop --port 8000
```

### Server Keeps Restarting

If the server keeps restarting due to programming errors, the development server will continue watching files and allow you to fix the errors without having to re-run the command.

## See Also

* [medusa start](./overview.mdx#development--build) - Start production server
* [medusa build](./build.mdx) - Build for production