<!--
{
  "documentType" : "article",
  "framework" : "AppKit",
  "identifier" : "/documentation/AppKit/app-extensions",
  "metadataVersion" : "0.1.0",
  "role" : "collectionGroup",
  "title" : "App Extensions"
}
-->

# App Extensions

Extend your app’s basic functionality to other parts of the system.

## Topics

### Extension Support

  <doc://com.apple.documentation/documentation/Foundation/NSExtensionContext>

  <doc://com.apple.documentation/documentation/Foundation/NSExtensionRequestHandling>

### Quick Actions

Quick Actions allow your app extension to appear in the Finder Preview pane, Quick Actions menu, and Touch Bar.

[Add Functionality to Finder with Action Extensions](/documentation/AppKit/add-functionality-to-finder-with-action-extensions)

Implement Action Extensions to provide quick access to commonly used features of your app.

  <doc://com.apple.documentation/documentation/BundleResources/Information-Property-List/NSExtension/NSExtensionAttributes/NSExtensionServiceAllowsFinderPreviewItem>

  <doc://com.apple.documentation/documentation/BundleResources/Information-Property-List/NSExtension/NSExtensionAttributes/NSExtensionServiceFinderPreviewLabel>

  <doc://com.apple.documentation/documentation/BundleResources/Information-Property-List/NSExtension/NSExtensionAttributes/NSExtensionServiceFinderPreviewIconName>

  <doc://com.apple.documentation/documentation/BundleResources/Information-Property-List/NSExtension/NSExtensionAttributes/NSExtensionServiceAllowsTouchBarItem>

  <doc://com.apple.documentation/documentation/BundleResources/Information-Property-List/NSExtension/NSExtensionAttributes/NSExtensionServiceTouchBarLabel>

  <doc://com.apple.documentation/documentation/BundleResources/Information-Property-List/NSExtension/NSExtensionAttributes/NSExtensionServiceTouchBarIconName>

  <doc://com.apple.documentation/documentation/BundleResources/Information-Property-List/NSExtension/NSExtensionAttributes/NSExtensionServiceTouchBarBezelColorName>

### Mail Extensions

  <doc://com.apple.documentation/documentation/MailKit/build-mail-app-extensions>

### UTI Subtypes for Data Detector Types

[`let NSTypeIdentifierAddressText: String`](/documentation/AppKit/NSTypeIdentifierAddressText)

[`let NSTypeIdentifierDateText: String`](/documentation/AppKit/NSTypeIdentifierDateText)

[`let NSTypeIdentifierPhoneNumberText: String`](/documentation/AppKit/NSTypeIdentifierPhoneNumberText)

[`let NSTypeIdentifierTransitInformationText: String`](/documentation/AppKit/NSTypeIdentifierTransitInformationText)


---

Copyright &copy; 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)