The VK iOS SDK is a library for integrating iOS applications with the VK (VK.com) social network. It provides authentication via OAuth, API request execution with JSON parsing into model objects, and UI components for sharing, authorization, and captcha handling. The SDK features a modular architecture with distinct layers for networking (VKRequest, VKHTTPClient), API method wrappers (VKApi), dynamic object mapping (VKApiObject), and resource management (VKBundle). Key entry points include the VKSdk singleton for session management, VKApi for convenient API calls, and VKAuthorizeController/VKShareDialogController for UI flows. The SDK relies on system frameworks (UIKit, Foundation, WebKit) and includes an example demonstration application. While the codebase shows strong engineering in reusable components like VKRequest and VKApiObject, it exhibits some technical drift through deprecated APIs (UIAlertView) and version discrepancies between documentation and podspec.