<!--
{
  "documentType" : "article",
  "framework" : "Swift",
  "identifier" : "/documentation/Swift/cocoa-design-patterns",
  "metadataVersion" : "0.1.0",
  "role" : "collectionGroup",
  "title" : "Cocoa Design Patterns"
}
-->

# Cocoa Design Patterns

Adopt and interoperate with Cocoa design patterns in your Swift apps.

## Topics

### Common Patterns

  <doc://com.apple.Swift/documentation/Swift/using-key-value-observing-in-swift>

  <doc://com.apple.Swift/documentation/Swift/using-delegates-to-customize-object-behavior>

  <doc://com.apple.Swift/documentation/Swift/managing-a-shared-resource-using-a-singleton>

  <doc://com.apple.Swift/documentation/Swift/about-imported-cocoa-error-parameters>

  <doc://com.apple.Swift/documentation/Swift/handling-cocoa-errors-in-swift>


---

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)