Mobile apps are expected to generate over $935 billion in revenue by 2023. With the robust increase in revenue, it’s no surprise that businesses are considering investing in mobile app development services. 

Nowadays, there is a buzz around Flutter and Kotlin in the mobile development industry, and the question on everyone’s mind is Flutter Vs. Kotlin, which one should I use? 

Flutter and Kotlin have become the most popular frameworks for developing cross-platform apps. While it’s true that both of them offer all the features needed for developing cross-platform apps, some subtle differences between the two make them suitable for different types of apps.

Flutter and Kotlin are both used to build apps for Android and iOS. 

The noticeable difference between both is: Flutter is a framework, and Kotlin is a programming language. 

However, both technologies are geared to take mobile app development to the next level, are backed by Google and use native performance to deliver the best apps across multiple devices. 

This blog will look at both of them, compare their features, and help you decide which is best for your next project.

Let’s dive in!

What is Flutter?

Flutter is a cross-platform, open-source, and free-to-use mobile app development framework created by Google in 2017. It allows developers to create beautiful, faster, natively-looking Android, Mac, iOS, Windows, and Linux apps.

Moreover, it allows you to build web, mobile, and desktop apps with a single codebase and one programming language. The best thing about using Flutter is that you can design any user interface without using native platforms.

Flutter uses Dart programming language to build fast, high-quality, responsive apps. The popularity of Flutter is increasing rapidly due to its cross-platform abilities.

In fact, most popular brands use this technology for app development, including

• Google Ads
• Tencent
• Square
• eBay

Pros of Flutter (can add null safety)

Flutter is a mobile app SDK that allows you to create high-quality native apps for iOS and Android without having to learn two different programming languages.

There are many advantages to using Flutter, including the following:

1. Hot-Reload

Flutter allows you to make changes to your code and see the changes in real-time while editing code, fixing errors, or adding features. The most significant benefit of the hot reload is that it reduces the need for fill time from the beginning. It saves you time developing the app and ensures that the changes made to the application are viewed instantly.

2. Null Safety

The best thing about Flutter is that it provides null safety elements to eliminate bugs and runtime errors caused by null pointers quickly. In general, null dereference errors are challenging to identify and resolve. Therefore, Flutter uses the null safety element to make the SDK better and run applications in an absolute sense.  

3. Open-source and free-to-use

As we’ve discussed above, Flutter uses Dart programming language, and both are open-source. So developers can easily access the documentation and code for free to analyse the queries in the developer forum.

4. Ideal for creating MVPs and prototypes 

Another great thing about Flutter programming language is that it is very versatile. Flutter can be used to develop iOS and Android apps with less effort and cost. As a result, Flutter is an ideal choice for creating MVPs and prototypes.

5. One codebase for two platforms

Flutter uses the same codebase for both Android and iOS; you can easily port your app from one platform to the other with minimal effort. Now you don’t have to write a separate code for Android and iOS devices. 

6. Faster and more responsive apps

Flutter framework uses Dart programming language, which is compiled into native code, resulting in apps that are fast and smooth.

Cons of Flutter

1. Larger App size

Apps made with Flutter are relatively more significant in size, which makes it hard for developers to build apps that won’t occupy too much space on iOS and Android devices. And users don’t want to download the app, which takes up more space on a device.

2. Lacks password manager support

Flutter lacks a few features on Android and iOS devices. The main issue in the apps made with Flutter is autocompleting input fields. Developers still need to extract security passwords from third-party or built-in administrators.

3. Limited third-party libraries

Flutter is still relatively new; a smaller pool of resources and libraries is available compared to more established platforms like iOS and Android. It can make it more challenging to find help when needed and potentially lead to more bugs.

What is Kotlin?

Kotlin is a general-purpose programming language developed by Jet Brains in 2016. It is a statistically typed language that targets the JVM (Java Virtual Machine) and Javascript. 

Kotlin multiplatform is designed to be a more concise, readable, and safe alternative to Java. It allows developers to share logic, code, and data across Android, iOS, Linus, Web, and macOS platforms. 

Also, it is interoperable with Java, meaning it can be used alongside existing Java code and libraries. 

Kotlin is currently one of the best cross-platform mobile app development frameworks, and it is used by multiple brands, including:

• Yandex
• Autodesk
• Netflix
• Pinterest
• Careem
• Vmware

Pros of Kotlin Multiplatform

1. Interoperable with Java

Kotlin provides an ‘Interoperable’ feature, meaning a developer can use all the java libraries and frameworks. Also, Kotlin uses java code which makes it interoperable with Java.

You can also store the old apps created with Java, create new Kotlin-based apps, and convert the apps into one file without starting the process from scratch.

2. Concise and Clear Code

Kotlin is a concise, clear, and expressive language that is easy to read and write. It allows developers to write less code which saves time and money. 

3. Null safety

Kotlin is also null-safe, meaning that you can avoid the dreaded NullPointerException.

4. Simple and easy language

One of the best benefits of Kotlin programming language is its simple syntax. If you know languages like Java, Groovy, Scala, and Swift, learning Kotlin will be easy for you.

5. Increased Performance

This Kotlin advantage is valuable because it compiles code to the same format as the targeted platform. As a result, it performs well as its native counterparts.

6. Reuse of Business Logic 

Cross-platforms like React Native and Xamarin provide separate UI and business logic. But with Kotlin, developers can now easily access shared logic and libraries within the UI layer. 

Cons of Kotlin 

1. Slower Compilation Speed

When Java and Kotlin compete against each other in different aspects of development, Kotlin usually comes out ahead in speed. However, this does not mean that Java is not a clear winner, as it can still produce clean applications faster than Kotlin. The fast pace of Kotlin may be offset by its inability to produce clean, functional applications.

2. New Language

First, Kotlin is a relatively new language, so there is less community support available compared to more established languages. As a result, it can make it difficult to find answers to questions or to get help when encountering problems. 

3. Limited Resources

With the rise in the popularity of Kotlin, Java developers are moving to Kotlin. But the developer’s community is still limited, and the number of Kotlin developers is less. Therefore,  the developers find it hard to learn this language due to the lack of learning resources.

4. Expensive

Building a mobile app with Kotlin is expensive due to the semi-native functionalities of the Kotlin SDK. It can pose a challenge compared to other programming languages, especially when working on prototypes or MVPs.

5. Time-consuming

Another potential downside of Kotlin is that it is not fully compatible with all Java libraries and frameworks. It means developers may need extra work to get Kotlin code to play nicely with existing Java-based projects. So it may take more time to write code in Kotlin than in Java.

Kotiln vs Flutter Comparison Factors 

1. Market Popularity

Both Flutter and Kotlin are popular for mobile app development because they are open-source and free-to-use tools.

This Google trends data of the past 5 years shows that developers are interested in working with Flutter and Kotlin both. A red line represents the Flutter, and a blue line represents the Kotlin.  

As you can see in the above image, the popularity of Flutter is rising compared to Kotlin.  Similarly, Flutter has 146k stars and 23.6k forks on Github. On the flip side, Kotlin has 43k stars and 5.3k forks.

This data indicates that Flutter has gained more popularity than Kotlin.  

2. Learning Curve

Flutter and Kotlin are two popular options for mobile app development. However, the learning curve is one of the essential factors for developers when choosing the application development framework. 

When considering the learning curve, Kotilin is easier to learn from different courses and is also interoperable with Java. Additionally, Kotlin syntax is relatively simple and easy for developers familiar with other languages, such as Java and Swift. 

However, there are limited resources and documentation available for Kotlin Multiplatform compared to Flutter. Contrary, Flutter uses Dart programming language and has comprehensive documentation available in the market.

3. Performance

Flutter programming language provides a hot reload feature, making it easy for developers to view the change instantly at the backend and front end simultaneously.

In contrast, Kotlin compiles code in the exact format requested by the targeted platform, increasing app development’s performance. It also offers native features like a Camera, Bluetooth, and much more.

4. User Interface Experience

When considering the cross-platform application, UI plays an essential role in the development process. It is because the main task of any cross-platform app is to provide a native experience.

With Flutter, you don’t have to compromise with the native user experience. Instead, it is a widget-oriented cross-platform framework that offers numerous customisable options so that developers can deliver better native performance with a single codebase.

In contrast, Kotlin offers flexibility to developers to customise the UI experience and build an application without any restrictions.

5. Documentation and Community Support

Kotlin is a relatively new framework in the market compared to Flutter, and it is still in the experimental stages. 

For this purpose, Kotlin has less documentation and community support. But with time, the Kotlin community is making efforts to increase the community members and make Kotlin the best choice for app development.

Flutter is constantly growing its user base and improving its comprehensive documentation for developers.

6.  Scope in Backend Development

When considering backend development, Flutter uses Firebase (Backend-as-a-service) to write effective code at the backend. On the other hand, Kotlin multiplatform allows developers to write backend code without extra effort.

Kotlin vs Flutter: The Ultimate Comparison

Here’s the ultimate comparison that explains the major differences between Kotlin and Flutter:

Conclusion: Flutter vs Kotlin

It is essential to understand that there is no ideal framework and language because Flutter and Kotlin both have pros and cons. However, they both are capable and reliable for developing cross-platform apps on Android and iOS devices.

Flutter is a new toolkit from Google for building cross-platform mobile apps, and Kotlin is a new language you can use to build Android apps.

Both give tough competition to each other. But if you are still confused about which framework to choose for your mobile app, you should consult an app development company and select the cross-platform app based on your requirements. 

Wish you all the best!