Flutter vs. Kotlin: Which Framework Is Right for Your Next Project? Mobile App Development

Flutter and Kotlin have both become popular platforms for Android app development. And for good reason — both have some strong developer-friendly features which make them powerful and easy to use. 

But which is the right choice for your project? To make your decision easier, we’re performing a detailed comparison between Kotlin and Flutter for Android app development. 

First, let’s take a quick look at both of these platforms. 

Flutter

Created by Google using Dart, Flutter is a framework for building natively compiled mobile, web, and desktop apps. It’s one of the most popular frameworks in use today. 

The BMW Group used Flutter to offer a unified experience to customers regardless of platform (Source: Flutter.dev)

With Flutter, you can build apps for Android, iOS, Linux, Windows, Mac, Web and more using a single codebase. Flutter is completely open-source and has a rapidly-growing community. 

Pros

• Flutter is easy to navigate and use, and can be quickly learned thanks to its user-friendly documentation.
• Its hot reload feature allows changes made in the backend to be viewed in the frontend in real-time, with no need to reload the entire app. This allows for a significantly faster pace of development with easy prototyping and tweaks. 
• Flutter is highly customizable through widgets, making software development easier and faster.
• It offers high performance which is a close second to native apps.
• Integration with the real-time cloud-hosted database Firebase makes it easy to store, manage and access data.
• Flutter makes it very easy to create cross-platform apps, which has made it the go-to platform for many programmers.
• Flutter is open-source and completely free to use.

Cons

• Flutter is not as widely adopted as some other platforms, so it may not be supported by platforms like Jenkins, Travis and others.
• It may not offer as many educational resources as languages like Java, JavaScript, C#, and C.
• Flutter is a large framework that results in large app sizes relative to other frameworks, making it a bad fit for complex projects.
• Dart is easy to learn but not commonly known among developers.

Also Read: Top 10 Amazing Apps Built with React Native

When to use Flutter

• In projects with frequent changes — the hot reload feature allows quick execution of code changes.
• When working with limitations in terms of time, resources, and cost — Flutter offers easy setup and usability and access to native-like features like geolocation, camera, and more. This makes it a great choice for building MVPs and prototypes.
• For apps that require high user engagement, such as business and enterprise apps, online stores, etc.

Kotlin

Kotlin is a cross-platform general-purpose programming language developed by JetBrains. It is fully interoperable with Java. Kotlin is also open-source and has been supported by Google since May 2019 for mobile app development on Android.

Netflix used Kotlin Multiplatform to build an app called Prodicle to innovate in the production of its video content (Source: Netflix Technology Blog)

Pros

• Kotlin is a mature language and ecosystem with robust tools on offer.
• Kotlin works well with Java. This makes it easy to migrate and maintain apps that use both languages, and also write code without migrating all the code. 
• Kotlin employs a syntax that’s similar to Java, Scala and Groovy. This makes it easy to learn for those familiar with Java, and makes the code concise and readable. 
• Kotlin offers higher code safety because of error detection by its compiler. This results in fewer bugs, errors and mistakes and higher application reliability. 
• Kotlin Multiplatform makes it easy to build cross-platform apps where developers share code and business logic across platforms like iOS, Android, web — speeding up development, reducing errors and bugs, and making the code easy to maintain. 
• Kotlin is scalable and flexible.

Cons

• App development in Kotlin can be expensive even though the platform is free. 
• Kotlin is a relatively new language that needs to be learned.
• Kotlin has relatively few libraries available.
• It has a slower compilation speed as compared to Flutter. 

When to use Kotlin

• When Java compatibility is important, e.g. adding features to an existing Java-based app. By using Kotlin in such a scenario, developers can make necessary changes without any major effort. 
• For apps that demand complex code — Kotlin uses intuitive syntax, making it easy to build and maintain large and complex apps.
• When you might need extensive debugging — Kotlin’s compiler reports and resolves crashes, finding bugs automatically and preventing them from occurring again. 

A detailed comparison between Kotlin and Flutter 

Now let’s consider a few aspects of each of these platforms in a bit more detail. 

Popularity

While both of these platforms are experiencing a steep rise in popularity, in the comparison between Kotlin and Flutter, Flutter is definitely the winner. Flutter is more widely used and its adoption is growing faster than that of Kotlin. 

Learning curve

Kotlin is interoperable with Java and has the advantage of using simple syntax that is similar to Java and Swift. But documentation and resources for Kotlin may be limited. For this reason, it may be easier to learn for those already familiar with the Java ecosystem. 

IT virtualization experts VMware used Kotlin Multiplatform Mobile to build their suite of productivity apps (Source: Play Store)

On the other hand, to use Flutter, developers need to learn the Dart programming language from scratch. But extensive documentation is available for Flutter, making it easy to pick up. 

Performance

Both Flutter and Kotlin deliver great performance. 

Flutter allows you to compile directly to machine code, which means Flutter apps are amazingly fast. It comes with a rich set of widgets, allowing you to achieve close to native performance. 

On the other hand, Kotlin compiles code in the same format as the target platform. While both are close competitors in this category, this aspect makes Kotlin perform better. 

Time to market

Flutter is easier to set up and configure on different development environments such as Visual Studio Code and Android Studio. Its hot reload feature makes it easy for developers to view changes made in real-time, speeding up development. 

While Flutter probably has a shorter time to market because of these reasons, Kotlin also offers advantages like concise syntax and code reuse which speed up the time to market. 

Must Read: Choosing the Best Programming Language for Android App Development: Kotlin vs. Java

Frontend and backend capabilities

Flutter is well known for its beautiful UI. It is very easy to use and offers a range of customization options through widgets. While its strengths lie in the frontend, it also has strong backend capabilities, but it may require a bit more effort to enable these. 

eBay Motors used Flutter to develop new apps for Android and iOS, saving a lot of development time with apps that share 98.3% of their code (Source: Flutter.dev)

On the other hand, being a general-purpose programming language, Kotlin offers a great deal of flexibility for developers to build and customize their apps as needed. It’s a good choice for building large and complex applications that would be slightly harder to achieve with a framework like Flutter. 

Community support and documentation

While Kotlin also has a robust community of developers, the Flutter community is more active with greater participation. Flutter’s documentation is also more detailed and up to date. 

A qualified partner can help you make the right choice

It can be tough to decide whether you should use Flutter or Kotlin for Android app development. Both Flutter and Kotlin are reliable platforms with some striking elements that make them strong competitors. Both offer native-like performance and cross-platform development options. 

Flutter makes it possible to experiment often and see changes in real-time, speeding up the time taken to add features, develop the UI, and fix any errors. If you’re building a minimal viable product (MVP) or quick prototype, Flutter is a good choice for you. But Kotlin may be the better choice for Android apps that require high performance. 

If you’re not sure whether you should be using Flutter or Kotlin for your Android app development, reach out to our team of experts for a consultation today — we can assess your requirements and help you make the right decision. 

Read Next: Choosing Your Cross-platform Mobile App Development Framework:  React Native vs. Flutter vs. Ionic