The AV Foundation framework provides an Objective-C interface for managing and playing audio-visual media in iOS and OS X applications.

Access network services and handle changes in network configurations. Build on abstractions of network protocols to simplify tasks such as working with BSD sockets, administering HTTP and FTP servers, and managing Bonjour services.

Core Foundation is a framework that provides fundamental software services useful to application services, application environments, and to applications themselves. Core Foundation also provides abstractions for common data types, facilitates internationalization with Unicode string storage, and offers a suite of utilities such as plug-in support, XML property lists, URL resource access, and preferences.

Use the Core Telephony framework to obtain information about a user’s home cellular service provider—that is, the provider with whom the user has an account. Carriers can use this information to write applications that provide services only for their own subscribers. You can also use this framework to obtain information about current cellular calls.

Core Text provides a low-level programming interface for laying out text and handling fonts. The Core Text layout engine is designed for high performance, ease of use, and close integration with Core Foundation. The text layout API provides high-quality typesetting, including character-to-glyph conversion, with ligatures, kerning, and so on. The complementary Core Text font technology provides automatic font substitution (cascading), font descriptors and collections, easy access to font metrics and glyph data, and many other features.

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.

Use uniform type identifier (UTI) information to create and manipulate data that can be exchanged between your app and other apps and services using MobileCoreServices.

Allow users to browse, edit, and save images, using slideshows and Core Image filters.The Quartz Composer API supports processing and rendering graphical data and allows developers to create custom patches for the Quartz Composer developer tool. ImageKit provides user interface support for browsing, editing, and saving images, showing slideshows, and browsing and previewing Core Image filters. PDFKit is a technology that allows applications to display and manipulate PDF documents.

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.

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.