Both Swift and Kotlin are excellent choices for modern development, with the best choice depending on the target platform and existing codebase. Swift is ideal for Apple ecosystem development, while Kotlin is a strong contender for Android and cross-platform development, especially when interoperability with Java is important.
| Attribute | Swift | Kotlin |
|---|---|---|
| Language Paradigm | Multi-paradigm, supporting protocol-oriented, object-oriented, functional, imperative, block-structured, declarative, and concurrent programming styles. | Multi-paradigm: object-oriented, functional, imperative, block-structured, declarative, generic, reflective, concurrent. |
| Platform Support | Apple's operating systems (iOS, iPadOS, macOS, tvOS, watchOS), Linux, Windows, and Android. | Android: Primary language for Android development. JVM: Targets the Java Virtual Machine. JavaScript (Kotlin/JS): For front-end web applications. Native (Kotlin/Native): macOS, iOS, tvOS, watchOS, Linux, Windows, WebAssembly, LLVM. |
| Syntax and Readability | Swift has a concise and expressive syntax that minimizes code verbosity. It is designed to be beginner-friendly, making it easier for developers to read and write code. Features like optionals and type inference enhance readability. | Concise and expressive syntax. Considered more modern and concise than Java, increasing code readability. Simple syntax with data classes, smart casts, and type interface. |
| Concurrency Model | Swift's concurrency model is built on threads, but developers don't directly interact with them. It uses asynchronous functions that can give up their thread, allowing other functions to run. Swift 5.5 introduced structured concurrency, including async/await, making asynchronous task management more predictable. Swift uses actors to protect against data races by ensuring only one piece of code at a time can access an actor's local state. | Uses coroutines for asynchronous programming, which are lightweight threads. Simplifies asynchronous programming, making it easier to handle concurrency and network requests. |
| Memory Management | Swift uses Automatic Reference Counting (ARC) to track and manage memory usage. ARC automatically frees up memory used by class instances when they are no longer needed. | Uses Garbage Collection (GC). Relies on the JVM's memory management model with automatic garbage collection. Kotlin/Native uses its own memory allocator, dividing system memory into pages for independent sweeping. |
| Null Safety Features | Swift incorporates optionals to handle nil values, reducing runtime crashes. Optionals explicitly declare when a value may be missing. | Explicitly supports nullability as part of its type system. Allows declaring which variables can be null. Enforces that non-null variables cannot hold a null value, preventing NullPointerExceptions (NPE). Uses nullable and non-nullable types. |
| Standard Library Completeness | Apple provides a wide range of libraries and frameworks through the Swift Standard Library and Cocoa Touch. The Swift Package Manager simplifies integrating third-party libraries. | Has its own standard library. Benefits from the extensive Java ecosystem. |
| Community Support and Ecosystem Size | Swift has a large and active community. Apple actively supports Swift through regular updates, and the community contributes to the language's evolution. | Growing community, especially in Android development. Strong support from Google and JetBrains. Access to the vast Java ecosystem. |
| Learning Curve for New Developers | Swift has a clean and intuitive syntax, making it easier to learn compared to Objective-C. | Moderate. Beginner-friendly syntax. Great tooling support. Easier for Java developers. |
| Performance Characteristics | Swift is designed to be fast, using LLVM compiler technology to transform code into optimized machine code. | Performance is comparable to Java. Coroutines can improve performance in concurrent programming. |
| Interoperability with Existing Code | Swift can interoperate with Objective-C code, allowing developers to use existing libraries and frameworks while migrating to Swift. | Designed to interoperate fully with Java. Seamless interoperability with Java simplifies migration for Android projects. Can leverage existing Java libraries and frameworks. |
| Job Market Demand and Salary Expectations | There is high demand for Swift developers, with a 15% annual growth in the job market. The average salary for a Swift Developer in the United States is $115,900 per year. | Growing demand in the job market. Kotlin developers are highly sought-after professionals. Average salary in the United States is around $130,813 annually (as of early 2025). Entry-level positions start around $115,000, while experienced professionals can earn upwards of $160,000 per year. |
| Price | Not available | Not available |