Objective-C

Objective-C is the legacy programming language that powered Apple platform development for over three decades before Swift’s introduction in 2014. As a superset of C with Smalltalk-style messaging, Objective-C brought object-oriented programming to iOS and macOS, enabling the entire ecosystem of apps that made the iPhone revolutionary. While its syntax with square brackets and verbose method names may seem antiquated to modern developers, Objective-C’s dynamic runtime and message passing architecture enabled powerful design patterns still used today.

Despite Swift becoming Apple’s preferred language, Objective-C remains relevant for several reasons. Millions of lines of production code exist in Objective-C, and many third-party libraries and frameworks haven’t been fully rewritten. Understanding Objective-C is essential for maintaining legacy codebases, integrating older libraries, and fully comprehending how iOS frameworks operate under the hood. Swift’s interoperability with Objective-C allows developers to gradually migrate projects while keeping existing code functional.

For new iOS projects, Swift is overwhelmingly the better choice, offering safety, modern syntax, and better performance. However, Objective-C skills remain valuable for senior developers working with mature codebases or debugging complex framework interactions. The language’s influence persists in many iOS design patterns and naming conventions still used in Swift APIs today.