---
title: App Extensions
framework: appkit
role: collectionGroup
role_heading: API Collection
path: appkit/app-extensions
---

# App Extensions

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

## Topics

### Extension Support

- [NSExtensionContext](foundation/nsextensioncontext.md)
- [NSExtensionRequestHandling](foundation/nsextensionrequesthandling.md)

### Quick Actions

- [Add Functionality to Finder with Action Extensions](appkit/add-functionality-to-finder-with-action-extensions.md)
- [NSExtensionServiceAllowsFinderPreviewItem](bundleresources/information-property-list/nsextension/nsextensionattributes/nsextensionserviceallowsfinderpreviewitem.md)
- [NSExtensionServiceFinderPreviewLabel](bundleresources/information-property-list/nsextension/nsextensionattributes/nsextensionservicefinderpreviewlabel.md)
- [NSExtensionServiceFinderPreviewIconName](bundleresources/information-property-list/nsextension/nsextensionattributes/nsextensionservicefinderpreviewiconname.md)
- [NSExtensionServiceAllowsTouchBarItem](bundleresources/information-property-list/nsextension/nsextensionattributes/nsextensionserviceallowstouchbaritem.md)
- [NSExtensionServiceTouchBarLabel](bundleresources/information-property-list/nsextension/nsextensionattributes/nsextensionservicetouchbarlabel.md)
- [NSExtensionServiceTouchBarIconName](bundleresources/information-property-list/nsextension/nsextensionattributes/nsextensionservicetouchbariconname.md)
- [NSExtensionServiceTouchBarBezelColorName](bundleresources/information-property-list/nsextension/nsextensionattributes/nsextensionservicetouchbarbezelcolorname.md)

### Mail Extensions

- [Build Mail App Extensions](mailkit/build-mail-app-extensions.md)

### UTI Subtypes for Data Detector Types

- [NSTypeIdentifierAddressText](appkit/nstypeidentifieraddresstext.md)
- [NSTypeIdentifierDateText](appkit/nstypeidentifierdatetext.md)
- [NSTypeIdentifierPhoneNumberText](appkit/nstypeidentifierphonenumbertext.md)
- [NSTypeIdentifierTransitInformationText](appkit/nstypeidentifiertransitinformationtext.md)

## See Also

### App Structure

- [App and Environment](appkit/app-and-environment.md)
- [Documents, Data, and Pasteboard](appkit/documents-data-and-pasteboard.md)
- [Cocoa Bindings](appkit/cocoa-bindings.md)
- [Resource Management](appkit/resource-management.md)