Alamofire is an HTTP networking library written in Swift. Think of it as AFNetworking, reimagined for the conventions of this new language.
Of course, AFNetworking remains the premiere networking library available for Mac OS X and iOS, and can easily be used in Swift, just like any other Objective-C code. AFNetworking is stable and reliable, and isn't going anywhere. But for anyone looking for something a little more idiomatic to Swift, Alamofire may be right up your alley. (It's not a mutually-exclusive choice, either! AFNetworking & Alamofire will peacefully co-exist within the same codebase.)