The Accounts framework provides access to user accounts stored in the Accounts database. An account stores the login credentials of a particular service, such as Twitter, that can be used as authentication for the service. By implementing the Accounts framework into your app, you do not need to be responsible for storing account logins yourself. Instead, the user can grant access for your app to use their account login credentials, bypassing the need to type their username and password. If no account for a particular service exists in the user’s Accounts database, you can let them create and save an account from within your app.

The Address Book framework provides access to a centralized contacts database, called the Address Book database, that stores a user’s contacts. Applications such as Mail and Messages use this database to present information about known and unknown persons.

In iOS and OS X, the Photos framework (formerly known as Assets Library framework) provides classes that support building photo editing extensions for the Photos app. In iOS, the Photos framework also provides direct access to the photo and video assets managed by the Photos app, including the iCloud Photo Library. Use this framework to retrieve assets for display and playback, edit their image or video content, or work with collections of assets such as albums, moments, and iCloud Shared Albums.

Bolts is a collection of low-level libraries designed to make developing mobile apps easier.

The Core Bluetooth framework provides the classes needed for your iOS and Mac apps to communicate with devices that are equipped with Bluetooth low energy wireless technology.

Core Image is an image processing and analysis technology designed to provide near real-time processing for still and video images.

The Core Motion framework lets your application receive motion data from device hardware and process that data. The framework supports accessing both raw and processed accelerometer data using block-based interfaces. For devices with a built-in gyroscope, you can retrieve the raw gyro data as well as processed data reflecting the attitude and rotation rates of the device. You can use both the accelerometer and gyro-based data for games or other apps that use motion as input or as a way to enhance the overall user experience.

Core Text is an advanced, low-level technology for laying out text and handling fonts.

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The EventKit framework provides classes for accessing and manipulating calendar events and reminders.

A full suite of services created by the team that brought you Crashlytics. Fabric provides monetization, engagement and other uses for developers beyond crash reporting.

The iOS SDK provides Facebook Platform support for iOS apps.