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

# App Sections

> Distribute custom iframe sections with your app

App Sections are similar to [embedded sections](/embedded-sections/overview), but are distributed with your app. You specify the App Section at the app level, and anyone that installs your app will be able to add it to their shop.

## Signature

The signature for app sections works exactly the same as [embedded sections](/embedded-sections/signature), but instead uses your app HMAC secret (also used to verify app webhooks). You can find the app HMAC secret in your [App settings](https://my-shop.fourthwall.com/admin/dashboard/settings/platform-apps?redirect).

## Message passing

<Note>
  The messages are different from embedded sections.
</Note>

### Resize

```json theme={null}
{
  "type": "RESIZE",
  "data": {
    "height": 100
  }
}
```

### Close

```json theme={null}
{
  "type": "CLOSE"
}
```

## Settings

We have an experimental feature that allows you to configure settings for your app section. Contact support on Discord to get access.