Kotlin Vs. Swift Programming Language

Kotlin and Swift are two relatively new programming languages that have generated a lot of interest among developers and technology experts.

Both languages have received plenty of positive reviews from software industry experts.

Developers new to these languages are wondering about the pros and cons of Kotlin vs Swift. In this article, I intend to compare the two languages to see exactly how they shape up.

Contents

What is Kotlin: An introduction
Swift: A brief overview
Kotlin vs Swift comparison:
Weighing between Kotlin and Swift for your strategic project?

What is Kotlin: An introduction

Kotlin has attracted a lot of attention in recent years regarding its use in Android development. The following are a few important facts about Kotlin:

  • JetBrains, the company that made the popular “Integrated Development Environment” (IDE) IntelliJ IDEA has developed Kotlin.
  • A statically-typed language, Kotlin requires developers to specify the types of variable they use. The type-checking, i.e., verifying and enforcing the constraints of types happen during compilation. This is different from dynamically-typed languages like Ruby where type-checking takes place during the run time. Read “I finally understand static vs. dynamic typing and you will too!” for more insights on this aspect.
  • Software engineers who built Kotlin took inspiration from other well-known programming languages like Java, Python, Scala, and C#.
  • They wanted to design an object-oriented language that compiled as fast as Java.
  • Kotlin is fully interoperable with Java. It can execute on “Java Virtual Machine” (JVM), moreover, it uses Java standard libraries and classes. Kotlin also compiles to JavaScript.
  • Kotlin first emerged in 2011, however, the first stable release was in 2016.
  • Interest in Kotlin picked up significantly when Google announced first-class support for the language in 2017.
  • Googles’ decision has to do with their long-drawn legal battle with Oracle. The lawsuit is over Googles’ use of Java “Application Programming Interfaces” (APIs) in their Android operating system (OS). Google evaluated alternatives, Kotlin is one. I have explained more on this in “Kotlin vs Java: which is the best choice?”.
  • Googles’ collaboration with JetBrains picked up the pace of its move to Kotlin. They formed the Kotlin Foundation in 2018.
  • Several releases of Kotlin brought about key enhancements. Kotlin v1.3.21 i.e., the latest stable release was announced in February 2019.

Swift: A brief overview

Apple, has been using Objective-C for a long time, however, they released their Swift language in 2014, something which indicated a strategic shift. Let’s examine a few points about this language:

  • Swift is a general-purpose, compiled programming language.
  • Software experts who designed Swift borrowed several ideas from Objective-C, Python, Ruby, and C#.
  • Developers can use Swift to code for iOS, macOS, watchOS, and tvOS.
  • Swift works seamlessly with the Cocoa and Cocoa Touch frameworks of Apple.com. In fact, Swift is built on the Cocoa framework, as this Quora Q&A thread points out.
  • Swift is definitely the language of choice as far as Apple is concerned, however, Objective-C code can still coexist with Swift code in the same app.
  • In addition to Apple, IBM also backs the Swift programming language.
  • There were several important releases of Swift. Swift v4.2.1, i.e., the latest stable release was launched in October 2018.
  • The rapid rise of Swift has clearly captured the imagination of the Apple developer community. Swift is growing in popularity, and you can read more about it in “Swift gains as iOS and macOS language, while Objective-C declines”.

Kotlin vs Swift comparison:

I will now compare Kotlin vs Swift using several criteria. Since each has its pros and cons, you will need to carefully consider your project requirement and choose the right language for you.

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Criteria #1: Target platform

As an entrepreneur or a developer, what is your target platform?

  • If Android is your target platform, Kotlin is the right choice.
  • Are you targeting iOS, macOS, watchOS, and tvOS? If so, then Swift suits your requirement.
  • On the other hand, outside of Android, Java still reigns supreme. Kotlin is gaining in popularity among Android developers, however, the overall Kotlin vs Java balance is still in favor of Java. Read “Kotlin gains ground in Android, but no current threat to Java, experts say” for more details.
  • Likewise, if you are looking beyond iOS, macOS, etc., then you will need a language other than Swift. Some experts have stated that developers can use Swift for Android development. Read “Swift on Android: the future of cross-platform programming?” for more information. However, this is certainly not an established practice.

Conclusion: Kotlin has the advantage of the larger market share of Android. However, Apple has dedicated and more spend happy buyers. So, if you intend to target that niche market, then you need to use Swift.

Criteria #2: The future of the language

You will want to invest your energy on a programming language that has a robust future. Given this, consider the following:

  • Apple is quite clear about using Swift for its various platforms. Swift certainly looks like the language of the future, as far as Apple is concerned. I have detailed this in my article “How to migrate your Objective-C project to Swift?”.
  • At the time of writing, there is no clear indication from Google about Kotlin and the company’s intentions regarding its future relationship. Google has certainly recognized it as an official language, and has undertaken a big push towards Kotlin. Having said that, they haven’t stated explicitly about its future role in its ecosystem.
  • At the same time, Google is also working on “Fuchsia”, i.e. their new operating system. They are using “Dart”, i.e., an easy-to-learn programming language to develop this. I have written about Dart in “How to deploy your Dart app to Heroku?”. There are questions about Fuchsia, for e.g., will it replace Android? Read more about such questions in “Google’s Fuchsia OS: everything you need to know”. Consequently, this has led to suggestions that Google will one day ditch  Kotlin.

Conclusion: At the time of writing, Swift is the clear winner, as Apple is fully backing it as their language of the future. We await similar clarity from Google about the future of Kotlin.

Criteria #3: Productivity gain

Productivity gain is an important criteria for entrepreneurs and developers alike. Kotlin vs Swift stack up as follows:

Kotlin

Kotlin offers an overall productivity gain because of the following:

  • Developers write less code, however, the code is easy to read. This is possible because of the concise syntax of Kotlin.
  • Kotlin Android developers can easily migrate their work-in-progress code to Kotlin.
  • Programmers can use Kotlin for functional programming. Read more about this in “Functional Kotlin”.
  • Full compatibility with Java helps developers since they can use Java libraries and frameworks.
  • Coders can eliminate errors easily with Kotlin, for e.g., the type system helps in pre-empting null pointer exceptions. A smaller codebase further helps in avoiding errors.
  • The small library of Kotlin eliminates runtime overheads.

Read more about the productivity benefits of Kotlin in “Kotlin vs. Java: 9 benefits of Kotlin for your business”.

Swift

Programmers can obtain higher levels of productivity using Swift because of the following:

  • Developers need to code less as Swift has operators for string control, class division, string concatenation, etc. Read more about it in “Objective-C or Swift: which technology to learn for iOS app development?”.
  • Swift is a lightweight language, as a result, the app is fast.
  • The language has features like generics and type interference, therefore, programmers can eliminate coding errors.
  • Swift has easier syntax, therefore, the code is more readable.
  • A smaller code base is easier to maintain.

You can review Swift productivity benefits in “Swift vs. Objective-C: 7 benefits of Swift development”.

Conclusion: Both Kotlin and Swift offer improved productivity, there’s nothing to choose between them with respect to this criterion.

Criteria #4: Availability of learning resources

Developers need access to learning resources when they start with a new programming language. In this aspect, Kotlin and Swift shape up as follows:

Kotlin

New programmers can access the following tutorials and learning resources:

Swift

Developers intending to learn Swift have several resources, as follows:

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Conclusion: Developers have access to high-quality learning resources for both Kotlin and Swift.

Criteria #5: Tooling support

Developers need robust tooling support in today’s Agile software development environment. How do Kotlin and Swift fare vis-à-vis this criterion? It turns out that both have adequate tooling support:

  • Android Studio, the popular Android IDE fully supports Kotlin. Developers can quickly start developing an Android app with it, using Kotlin. Follow the instructions in “Getting started with Android and Kotlin”.
  • Xcode, the IDE of choice for developers creating apps for popular Apple platforms provides extensive support for Swift. Xcode 10 include Swift v4.2, therefore, programmers get their apps compiled quicker.

Conclusion: Both languages have excellent tooling support, which helps developers.

Criteria #6: Overall support and community

In today’s era, a programming language relies on powerful backers as well as robust community support to grow.

In the aspect, Kotlin fares as follows:

  • Kotlin is an open-source language.
  • Google, the technology giant is backing it since 2017.
  • JetBrains, the creator of Kotlin is well-known in the software industry for their high-quality products like IntelliJ IDEA.
  • A vibrant community supports new and experienced developers. Check out the org community, or the discussion forum on the same website.

Swift isn’t lagging, as seen from the following indicators:

  • This is also an open-source language.
  • Apple and IBM are the technology powerhouses backing Swift.
  • A growing community supports developers in problem-solving and learning. You can visit the org community, for example.

Conclusion: Both languages can boast of vibrant and growing communities, in addition to powerful backers.

Criteria #7: Similarities and differences

In today’s software development environment, it’s common for developers from one platform to transition to another. Android developers might find that the one day they are being asked to develop an Android app, and the next day an iOS app.

Developers with knowledge of one language will need to learn another if they wish to work with big clients. The similarities and differences between languages becomes important in this context since they determine the learning curve.

Kotlin and Swift have the following similarities:

  • Both languages treat declaration of properties in similar ways. They both have mutable and immutable properties.
  • There are similarities in data structures, e.g., arrays, dictionaries, etc.
  • Kotlin and Swift treat functions in similar ways.
  • Both languages use unnamed functions. Kotlin uses “Lambda functions”, similarly, Swift uses “Closures”. Read more about it in “Practical Kotlin & Swift comparison”.
  • Kotlin and Swift programmers must specify whether a variable can contain a null value, which is a key similarity.
  • Both languages have similar coding for controlling the flow of a program, e.g., “If-Else”, “for loop”, etc.
  • Developers declare classes similarly in both languages.
  • Both languages use “Class extensions”.

Read more about these similarities in “A comparison of Swift and Kotlin languages”.

There are a few differences, e.g.:

  • Kotlin supports “data classes”, i.e., classes that primarily hold data. Read about it here. Swift doesn’t have these.
  • Kotlin has “delegated classes” that can access public methods of an interface through specific objects. Read more about it in “Kotlin – delegation”.
  • Swift supports “Tuples”, i.e., a type that can hold multiple values in a single compound value. Read more about it in “Swift – Tuples”. Kotlin doesn’t support this.
  • There are also a few syntax differences between Kotlin and Swift code, and you can find them in “Swift vs Kotlin — the differences that matter”.

Conclusion: There is always a bit of learning curve when transitioning from one language to the other. However, it’s not markedly different one way or the other when considering Kotlin vs. Swift.

Weighing between Kotlin and Swift for your strategic project?

If you are evaluating Kotlin vs Swift to see which to use for an important project, then you need to make sure that you make the correct choice.

The success of your project will depend on this. If you are still not sure after doing your research then consider consulting professional help from software development experts.

Our guide “How to find the best software development company?” can help you find the right experts for your project. Best of luck!

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