On June 2, 2014, at its Worldwide Developers Conference, Apple announced Swift alongside the iOS 8 SDK. Apple’s press release that day introduced it as “a powerful new programming language for iOS and OS X” designed to let developers “create incredible apps.”
The announcement positioned Swift as a faster, safer way to write software for Apple’s platforms. It said Swift combines “the performance and efficiency of compiled languages with the simplicity and interactivity of popular scripting languages,” and “helps developers write safer and more reliable code by eliminating entire categories of common programming errors.”
Crucially, Apple did not require developers to abandon their existing code. The release noted that Swift “coexists with Objective-C code, so developers can easily integrate Swift into their existing apps.” A beta version was made available to developers the same day, with the final version planned for the fall. Alongside the language, Apple introduced Xcode Playgrounds, which displayed the output of Swift code instantly as it was written.
The announcement marked the beginning of a long transition away from Objective-C, which had been Apple’s primary development language since the NeXT era. Swift would go on to be open-sourced in December 2015.