AFNetworking is an open-source networking library for macOS, iOS, watchOS, and tvOS. It provides an easy-to-use interface to make HTTP requests and handle server responses, making it easier for developers to build network-enabled applications. AFNetworking supports various protocols, including HTTP, HTTPS, and WebSocket, and offers features like JSON and XML parsing and file uploading. It is widely used in mobile application development and requires knowledge of objective-C or Swift programming languages.