Kotlin vs. Swift: A comparison of the two popular programming languages for developers

When it comes to mobile app development, businesses and developers face multiple choices in selecting the right technology. Among the most popular options for native app development are Kotlin and Swift, the official programming languages for Android (Kotlin) and iOS (Swift) respectively.

In this article we dive into the Kotlin programming language and the Swift programming language, comparing their strengths, weaknesses, and ideal use cases.

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Introduction to Kotlin and Swift

Kotlin and Swift have gained a lot of traction in the tech community for their efficiency and performance in mobile app development as they come with the most popular mobile platforms Android and iOS. Here’s a quick overview of each:

What is Kotlin?

What is Swift?

Kotlin and Swift share a lot of similarities — they’re both modern, statically typed, and emphasize safety. However, each has unique advantages suited to their respective platforms, which we will present in the following.

Kotlin vs. Swift: Comparison of programming languages and their advantages

Language Syntax Features and Readibility

The Kotlin programming language is highly influenced by Java but introduces more concise syntax to develop Android applications. Some of Kotlins’ key features and Kotlin advantages over Java are as follows:

• Null Safety: Kotlin’s null safety helps reduce the likelihood of null pointer exceptions, a common source of app crashes in Java.
• Coroutines: Kotlin offers coroutines to handle asynchronous tasks, making it easier to manage background processes without complex callback chains.
• Interoperability with Java: Kotlin is fully interoperable with Java, allowing developers to use Java libraries and frameworks within Kotlin codebases.

More functions that Kotlin has that Java does not can be found here.

The Swift programming language has a syntax like other modern languages but with a focus on simplicity and safety:

• Optionals: Swift’s optional types help manage the absence of values, reducing runtime errors associated with null pointers.
• Memory Safety: Swift’s memory management is one of the safest in the industry. It uses Automatic Reference Counting (ARC), which automatically handles memory usage without complex memory management from the developer.
• Playgrounds: Swift has a unique feature called Playgrounds, which enables developers to write Swift code and see results immediately, making it a useful tool for learning and testing code snippets.

In terms of syntax, both languages are similar, but Swift tends to be more beginner-friendly, while Kotlin, with its deep Java roots, may feel more familiar to experienced Android developers.

Performance

Since Kotlin and Swift are both compiled languages optimized for Android and iOS respectively, performance in native environments is typically strong.

Kotlin Performance: The Kotlin programming language compiles to Java bytecode (and can also compile to native code with Kotlin/Native). Performance is comparable to Java, and its coroutines improve responsiveness in applications that rely on background tasks.

Swift Performance: Swift’s performance has been optimized extensively by Apple to take full advantage of the iOS hardware. Swift generally outperforms Objective-C and, in many cases, offers comparable or superior performance to Kotlin in mobile app scenarios.

Development Experience: Tools and Libraries

Kotlin:With Kotlin programming language being officially supported by Google, it integrates seamlessly with Android Studio, providing a robust IDE experience. Developers benefit from a vast ecosystem of Java libraries and Android-specific APIs that help streamline app development.

Swift:The Swift programming language is supported by Xcode, Apple’s official IDE. While Xcode is generally considered stable and reliable, it can have a steeper learning curve. However, Swift’s integration with Apple’s frameworks, including UIKit and SwiftUI, makes it highly effective for building complex iOS applications.

Both languages have large communities, with numerous libraries, resources, and learning materials, which can ease the development process.

Job Market and Demand

For developers considering Kotlin or Swift, understanding the job market for each language is essential.

Kotlin: The demand for Kotlin developers is high, especially within Android app development. As more companies adopt Kotlin, including tech giants like Google, the demand for Kotlin expertise has surged. Additionally, Kotlin’s recent adoption for server-side and multi-platform development opens new career opportunities.

Swift: Swift developers are in high demand for iOS development. With Apple’s dominance in the mobile device market, companies constantly seek developers skilled in the Swift programming language. Swift’s simplicity and efficiency have also encouraged new developers to enter the iOS development space, creating a healthy job market for Swift developers.

The demand for both Kotlin developers and Swift developers is strong, with opportunities available for each in their respective ecosystems. This is also proven by the mentioned TIOBE index and the Stack Overflow Survey of 2023, where both programming languages were voted as popular and median salaries for Kotlin in comparison to Java were higher in 2023.

Disadvantages of Kotlin

• Slower Compilation Speeds: Kotlin can have slower compilation times than Java, especially during incremental builds, which may impact productivity in large projects.
• Limited Community and Learning Resources: Although growing, Kotlin’s community and resources are still smaller compared to Java, making it harder to find extensive libraries, documentation, and support for more niche use cases.
• Steeper Learning Curve for Java Developers: Java developers transitioning to Kotlin may initially find the syntax and concepts (like extension functions and coroutines) challenging, requiring a learning adjustment period.

Disadvantages of Swift

• Limited Cross-Platform Support: Swift is primarily focused on Apple ecosystems, limiting its usage to iOS, macOS, watchOS, and tvOS, which can be a drawback for developers needing a cross-platform solution.
• Backward Compatibility Issues: Swift undergoes frequent updates, and some versions are not backward compatible, which can create challenges in maintaining older codebases or projects developed with previous Swift versions.
• Smaller Talent Pool: Compared to more established languages like Java or JavaScript, there are fewer Swift developers, which can make hiring or collaborating on Swift projects more challenging, especially for non-Apple-focused companies.

Swift vs Kotlin: Which programming language is better?

When it comes to Kotlin vs Swift, the decision largely depends on whether you’re developing for Android or iOS and whether performance, native functionality, and language features are a priority.

Kotlin can also serve as a cross-platform development tool due to its interoperability with Java. If you are considering it, you should also look at other popular cross-platform app development framworks.

In a world with so many options, understanding the unique strengths of the Kotlin programming language and the Swift programming language, as well as weighing them against cross-platform frameworks, can help developers and businesses make informed, strategic choices for their app development needs. Whether you go native or choose a cross-platform framework, each option brings its own set of benefits that can power great mobile experiences for users.

Check out our Docutain SDK
Learn more about the Docutain SDK, providing document scanning, data capturing, OCR, data extraction and barcode scanning functionalities. It is available for Android and iOS.
If you want to test the Document Scanner SDK without writing any lines of code, check out our Showcase Apps for Android & iOS or have a look at our Kotlin example, Java example and Swift example in GitHub.