The Foundation framework provides a base layer of functionality for apps and frameworks, including data storage and persistence, text processing, date and time calculations, sorting and filtering, and networking. The classes, protocols, and data types defined by Foundation are used throughout the macOS, iOS, watchOS, and tvOS SDKs.

The UIKit framework (UIKit.framework) provides the crucial infrastructure needed to construct and manage iOS apps. This framework provides the window and view architecture needed to manage an app’s user interface, the event handling infrastructure needed to respond to user input, and the app model needed to drive the main run loop and interact with the system.

Display web content in windows. Implement browser features such as following user-activated links, managing a back-forward list, and managing a history of recently visited pages. WebKit provides a set of classes to display web content in windows, and implements browser features such as following links when clicked by the user, managing a back-forward list, and managing a history of pages recently visited. WebKit greatly simplifies the complicated process of loading webpages—that is, asynchronously requesting web content from an HTTP server where the response may arrive incrementally, in random order, or partially due to network errors. WebKit also simplifies the process of displaying that content which can contain various MIME types, and compound frame elements each with their own set of scroll bars. WebCore is a framework developed by Apple, and licence under the LGPL, to provide an HTML layout engine for Mac OS X. It is one half of WebKit (the other being JavaScriptCore). WebCore combines the open source KHTML layout engine developed by the KDE project, with an adapter library called KWQ (pronounced Quack). Apple created the KWQ adapter to replace KHTML's dependency on code from the Qt toolkit and other KDE modules. KWQ also presents an Objective-C application programming interface to the C++-based KHTML rendering engine, allowing it to easily be referenced by Cocoa-based applications.

Appcelerator Titanium – An open, extensible development environment for creating beautiful native apps across different mobile devices and OSs including iOS, Android, and BlackBerry, as well as hybrid and HTML5. It includes an open source SDK with over 5,000 device and mobile operating system APIs, Studio, a powerful Eclipse-based IDE, Alloy, an MVC framework and Cloud Services for a ready-to-use mobile backend.

The Google Data APIs (GData) provide a simple protocol for reading and writing data on the web. Each of the following Google services provides a Google data API: Blogger Calendar Calendar Resource Contacts Content API for Shopping Documents List Email Audit Email Settings Google Analytics Google Apps Provisioning Google Webmaster Tools Picasa Web Albums Spreadsheets YouTube