Swift is a general-purpose programming language. The open-source Swift project, hosted at Swift.org and led by its Core Team, develops it; Apple Inc. holds the Swift trademark and the copyright of the site. It is used for apps on all Apple platforms (iOS, macOS, watchOS, tvOS and visionOS), for command line tools, for server software on Linux, and for firmware on microcontrollers.
Swift compiles directly to native machine code, with performance on par with C-based languages. It is designed for safety: variables are always initialized before use, arrays and integers are checked for overflow, memory is managed automatically, and a value can be empty (nil) only when its type is declared as an optional, which the compiler checks. It supports object-oriented, functional and generic programming, and it can call C and C++ code directly. The toolchain includes the compiler, the standard library, the LLDB debugger and the Swift package manager, and it works with Xcode, Visual Studio Code and other editors.
Swift is free and open source under the Apache 2.0 license with a Runtime Library Exception.