> For clean Markdown of any page, append .md to the page URL.
> For a complete documentation index, see https://developers.webflow.com/designer/reference/extension-utilities/llms.txt.
> For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://developers.webflow.com/_mcp/server.

# Extension utilities

> Essential utilities for managing your Designer Extension's interaction with Webflow

The Designer API offers essential utilities to manage your extension's behavior and interaction with the Designer.

#### [Site information](/designer/reference/get-site-info)

Access site details and configure how your extension appears in the Designer

#### [User events](/designer/reference/events)

Subscribe to Designer events to create responsive extensions

#### [App discovery](/designer/reference/app-intents-and-connections)

Make your extension discoverable in element settings

#### [User authentication](/designer/reference/get-user-id-token)

Authenticate users with the Data API, and access Data API resources

## Best practices

#### Dynamic updates

[Subscribe to relevant events](/designer/reference/events) like when a user selects a new element to keep your extension in sync with the Designer state.

#### Appropriate sizing

[Size your extension appropriately](/designer/reference/resize-extension) with `resizeExtension()`. Too large and it dominates the UI; too small and it's hard to use.

> **Note**
>
> For a comprehensive guide to building effective extensions, check out our [Quick Start Guide](/designer/docs/getting-started-designer-extensions) and [App Setup](/designer/reference/app-structure) documentation.

> Essential utilities for managing your Designer Extension's interaction with Webflow

## Docs

- [Get site information](https://developers.webflow.com/designer/reference/get-site-info.md): 
- [Resize the extension](https://developers.webflow.com/designer/reference/resize-extension.md): 
- [Close the extension](https://developers.webflow.com/designer/reference/close-extension.md): Close the Designer Extension using the Webflow object
- [Get the current breakpoint](https://developers.webflow.com/designer/reference/get-breakpoint.md): 
- [Get all media queries](https://developers.webflow.com/designer/reference/get-all-media-queries.md): 
- [Get user ID token](https://developers.webflow.com/designer/reference/get-user-id-token.md): 
- [Get user's Designer capabilities](https://developers.webflow.com/designer/reference/get-users-designer-capabilities.md): 
- [Get the current Designer mode](https://developers.webflow.com/designer/reference/get-current-mode.md): 
- [Check for a Designer mode](https://developers.webflow.com/designer/reference/is-mode.md): 
- [Get the pseudo state](https://developers.webflow.com/designer/reference/get-pseudo-mode.md): Get the current pseudo-class state (e.g. hover, focus, pressed) of the designer.
- [Get Launch Context](https://developers.webflow.com/designer/reference/get-launch-context.md): Identifies how the Designer Extension was launched and provides context about the launching element.
- [Get App Subscriptions (Beta)](https://developers.webflow.com/designer/reference/get-app-subscriptions.md): Get all active app subscriptions for the current site.
- [Get Theme (Beta)](https://developers.webflow.com/designer/reference/get-theme.md): Get the currently active Designer appearance theme.
- [Get Theme Styles (Beta)](https://developers.webflow.com/designer/reference/get-theme-styles.md): Get the CSS design token values for a given Designer theme.
- [Get element snapshot](https://developers.webflow.com/designer/reference/get-element-snapshot.md): 
- [User events & notifications](https://developers.webflow.com/designer/reference/events.md): 
- [Send notification to user](https://developers.webflow.com/designer/reference/notify-user.md): 
- [User selects element](https://developers.webflow.com/designer/reference/user-selects-element.md): 
- [User changes breakpoint](https://developers.webflow.com/designer/reference/user-changes-breakpoint.md): 
- [User changes current page](https://developers.webflow.com/designer/reference/user-changes-current-page.md): 
- [User changes CMS Page](https://developers.webflow.com/designer/reference/user-changes-cms-page.md): 
- [User changes Designer mode](https://developers.webflow.com/designer/reference/user-changes-mode.md): 
- [User changes pseudo mode of Designer](https://developers.webflow.com/designer/reference/user-changes-pseudo-mode.md): User Event. Use this method to start listening for specific events in your App. In this case, we're listening for when a user changes the pseudo mode of the Designer.
- [User changes variant (Beta)](https://developers.webflow.com/designer/reference/user-changes-variant.md): 
- [App Intents and Connections](https://developers.webflow.com/designer/reference/app-intents-and-connections.md): Use App Intents and Connections to launch Apps directly from a user's workflow in the Webflow Designer
- [Set App Connection](https://developers.webflow.com/designer/reference/set-app-connection.md): Create a connection between an element and an App
- [Get App Connections](https://developers.webflow.com/designer/reference/get-app-connections.md): Get all App Connections associated with a specific element
- [Remove App Connection](https://developers.webflow.com/designer/reference/remove-app-connection.md): Remove an App Connection from an element
- [Get Current App Connection](https://developers.webflow.com/designer/reference/get-current-app-connection.md): Get the current App Connection identifier
- [Get Current App Connection Element](https://developers.webflow.com/designer/reference/get-current-app-connection-resource.md): Retrieve element that triggered the App Connection