Kotlin VS Flutter: Which One Races Ahead

Those days have long passed when cross-platform mobile applications used to have a single avenue—React Native. Things have changed very fast as people looked for new ways to gain more and more users in the mobile app domain.

Fast forward to 2016; we have Kotlin—a cross-platform, statically typed, general-purpose programming language with type inference. Around the same time, Flutter entered the arena—an open-source UI software development kit from Google's house, solidifying the parents’ reputation in the world of mobility. 

For businesses trying to enter the world of mobile app development, one of the most puzzling questions faced is—what could be the best framework/technology for building killer apps? 

In this article, I will talk about the distinctive features of Kotlin and Flutter that would enable readers to make an informed choice regarding the mobile app development platform. First things first, let us begin by giving a brief of both. 

Kotlin is a general-purpose programming language built to be interoperable with Java and its own Java Virtual Machine version. Its type-inference feature has enabled it to become concise.

It mainly targets Java Virtual Machine; however, it can also compile to JavaScript for front-end applications. Additionally, it can target native code using LLVM for iOS apps that share Android apps' logic. It was designed and developed by JetBrains—a Czech software development company. 

Google is the designer and developer of an open-source UI software development kit called Flutter. It can be used to build applications for Android, Windows, macOS, Linux, iOS, and Fuchsia—all using a single code base. Apps in Flutter are coded in Dart programming language.  

On Linux, macOS, and Windows—Flutter executes Dart virtual machine that has just-in-time execution capacity. Further, it also utilizes a just-in-time compiler for debugging and writing an application. It executes a ‘hot-reload,' through which—alterations to the source code can be done in a running app. It further uses this feature for stateful hot-reload through which changes in the code can be done immediately without a reboot. 

Flutter is composed of the following elements: 

Let us compare Kotlin and Flutter across various parameters enabling you to choose the right fit for your needs. 

UI Experience 

Choosing Flutter for app development would get you to make use of various widgets. These widgets shorten the development time by building a mobile solution in a customized, quick, and efficient manner. Flutter is, after all—a software development kit primarily meant to support UI development.  

Kotlin enables developers to have a bird's eye view at the apps’ execution, conduct, and appearance the way they want. It does not put any restrictions or pre-conceived guidelines—thereby empowering developers to utilize local widgets and libraries. This makes it quite similar to native app development. 

With Flutter, it is possible to use the same language for the front-end and backend. It has got better speed and higher performance. However, when compared to Kotlin, it lags very much. The main reason is that Kotlin code is compiled in the same format as that of the platform it is intended for. This feature makes Kotlin a very robust platform giving a better performance. Hence, in this aspect, Kotlin is the clear winner. 

Flutter and Kotlin being open source—are widely utilized across the world for cross-platform app development. As per Statista, Kotlin is among the top-10 wanted programming languages among developers worldwide, as of early 2020. If compared based on GitHub presence, Kotlin has 33K+ stars and 4K+ forks while Flutter is racing ahead with ~101K stars and ~14K forks. 

All research points in the direction that Flutter is hugely popular compared to Kotlin. 

Integration of Third-Party Libraries and Tools 

Kotlin works within the ecosystem of the native platform instead of having its own. It enables app developers to deploy the same libraries and third-party tools that they were using while natively developing apps such as SwiftUI and Jetpack Compose. It additionally gives developers the advantage of not looking for tools and libraries to connect with the native environment.  

In the case of Flutter SDK—it allows the calling of platform-certain APIs as available in iOS and Android languages such as Swift, Objective C, and Java. These platform-specific languages are not dependent on code generation but make use of flexible messaging.   

Here, I will list the specific advantages of using Flutter in app development. 

It is one of the most sought-after advantages of using Flutter in the app development domain. With hot-reload, it is possible for developers to make changes at the backend and, at the same time, see the changes getting implemented. As changes can be introduced simultaneously, it can be assessed if the changes are in sync with other app components. 

Flutter is made highly tailorable by the availability of numerous widgets present within the development ecosystem. Widgets make the app development process a highly customizable and creative experience. They fasten the process as well. 

Less Development Cost and Time  

Because Flutter can be used for creating mobility solutions that can run across various platforms using the same code—this considerably cut shorts the time to develop. Since the code is not be worked again and again for different platforms, the development resources needed come down as well. 

MVP and Prototype Development   

As Flutter is a cross-platform app development tool, less time and human resources are needed for creating apps across the platforms. As such minimum viable product development can be rushed and used for assessing if the idea is a good fit for scaling up. 

Below, I list the specific benefits of using Kotlin for mobile app development. 

Porting to Kotlin Not Needed 

Because Kotlin is a general-purpose programming language and not a software development kit—you do not have to port the whole application to it. Development can be started from a single component that can, later on, be integrated into the main module—if found suitable.  

Kotlin's syntax is similar to those of other programming languages such as Scala, Groovy, Java, and Swift. Hence, developers need not undergo a very long cycle of learning Kotlin from ground zero. 

Robust Performance 

Kotlin is very suitable for cross-platform mobile app development because it compiles code according to the targeted platform. This is very advantageous as it provides the level of performance at par with native app development. 

Scalability and Flexibility 

With Kotlin, developers can scale up the app development project without making use of Virtual Machine. The scalability and flexibility offered by Kotlin make it a perfect choice for building a cross-platform mobile app. 

Let me be obvious that all the app development technologies/platforms, be it—React Native, Kotlin, or Flutter—are made for easing some of the problems. However, it is also a fact that nothing is perfect in this world, and no single technology can solve all of the issues. 

If very enhanced UI levels are not desirable and you are in a hurry to launch the app somehow—go for Flutter. It is so because it offers end-to-end development. Things would be done for your satisfaction. However, if you want to implement an optimized and tailored user interface that is high on business logic—nothing can beat Kotlin.