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.

AFNetworking is a networking library for iOS and Mac OS X. It's built on top of the Foundation URL Loading System, extending the powerful high-level networking abstractions built into Cocoa. It has a modular architecture with well-designed, feature-rich APIs that are a joy to use.

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

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.

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

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

Dictionary Services provides functions that let you access dictionaries programmatically from within your application.

To make things as easy as possible, we have several platform SDKs you can import into your development environment to get up and running quickly. The SDKs contain platform-specific libraries that wrap the raw HTTP calls to the Dropbox API. They are designed to shorten the distance between your application and integrating Dropbox.