Swift is an application and systems programming language developed by Apple and distributed as open source. Swift interoperates with Objective-C and Cocoa/Cocoa touch APIs for Apple’s macOS, iOS, tvOS, and watchOS operating systems. Swift currently supports macOS and Linux. Community efforts are in progress to support Android, Windows, and other platforms.
Swift development happens on GitHub; contributions are usually submitted via pull requests.
Bugs and other issues are tracked at bugs.swift.org.
Discussions about Swift development, evolution, and usage are held on the Swift mailing lists.