Last.fm iOS and Mac OS X SDK is a development kit created Kevin Renskers. Using the SDK, developers can work with blocks, use only KissXML as a dependency, return values in correct data types, hook catching methods, and cancel operations. This kit is actively developed and maintained and used in the official Last.fm Scrobbler app. Other apps using Last.fm include MetroLyrics and Radio.com. Requirements to develop include iOS 4 and Xcode 4.4 or higher, an API Key obtained at last.fm/api, and Kiss XML.