What is Swift?

Swift is a powerful, open-source, general-purpose programming language developed by Apple and announced in 2014. It was designed to replace Objective-C for iOS, macOS, watchOS, tvOS, and server-side development. Key characteristics: (1) Safe: null safety via Optionals eliminates a whole class of null pointer exceptions; type safety prevents type mismatches at compile time; bounds checking on arrays; (2) Fast: compiled to native machine code via LLVM, comparable to C++ performance; (3) Expressive: clean, concise syntax inspired by Python, Ruby, and Rust; type inference reduces verbosity; (4) Modern: closures, generics, protocol-oriented programming, value types, async/await concurrency; (5) Interoperable: works seamlessly with Objective-C code in the same project. Swift is strongly, statically typed — types are known at compile time but often inferred. Since 2015, Swift has been open source (github.com/apple/swift) and runs on Linux and Windows. Swift 5.9+ features macros, parameter packs, and SwiftData. Swift is consistently ranked among the most loved programming languages in developer surveys.