Flutter vs Kotlin: Which to Choose for Cross-platform App Development?

  • Do you want to build scalable, stable, and robust applications?
  • Do you have a limited budget and are looking for a quicker time to market?
  • Is the user interface the most important criteria for you?

In such a scenario developing a cross-platform mobile app development is one of the best solutions.

The reason behind developing cross-platform apps is they can be developed quickly for multiple platforms from a single codebase. Here’s one of the research from Researchgate, which depicts the importance of cross-platform app development in the era of the app development world.

When it comes to cross-platform application development, entrepreneurs rely on Flutter, React Native, Ionic, and Xamarin. However, there is one new cross-platform language that is gaining attention named Kotlin.

Since Flutter has gained much attention in the IT market, we have compared Flutter and Kotlin. So, if you are searching for Flutter vs Kotlin for cross-platform app development, you have landed at the right place.

You may end up with multiple blogs, but in our blog, you will get the real solution of choosing Kotlin Multiplatform or Flutter as per your requirements. So yes, the actual comparison is between Kotlin Multiplatform Mobile (newly released cross-platform SDK by Kotlin) and Flutter.

So which one fits your requirements?

Let’s discuss further.

What is Flutter?

Flutter is Google’s open-source technology used to create apps and web apps for desktop, iOS, and Android. Released in May 2017, it is a mobile UI framework, freely available and enables the creation of native mobile applications with a single codebase.

This means only one programming language and one codebase is used to create two different apps for iOS and Android. This results in building iOS and Android apps simpler, quicker, and faster.

Flutter consists of two parts:

  1. Software Development Kit (SDK): A collection of tools to develop the applications. It even has the tools which can help to compile code into native machine code.
  2. Framework: A collection of UI elements like buttons, text inputs, sliders to personalize the project as per the requirements.

Dart programming language created by Google is used to develop an app in Flutter. Dart focuses on front-end mobile app development and can be used to develop mobile and web applications. Companies that have developed applications in Flutter include ByteDance, Dream11, eBay, and Hamilton.

Space-O being one of the leading Flutter app development companies has experienced Flutter app developers who can build customized app in Flutter. The developers of Space-O technologies have created one of the popular ride-sharing platforms in Flutter which helps to book taxis on-demand.

Moreover, the entire Google Pay was rewritten in Flutter to drive global product development. When they started using Flutter, here’s how the success metrics looked like:

google pay with flutter

And here’s what Google Pay director David Ko had to say about Flutter.

Google Pay director David Ko

Want to know which other companies have integrated Flutter, what was their success ratio, and how Flutter development helped enterprises to grow?
Explore this blog about Flutter app examples to know more.

Features of Flutter

  • Sharing UI and business logic is possible in Flutter which saves time and development.
  • Provides a set of materials and Cupertino widgets which makes the process faster and simpler.
  • Provides declarative API for building UI, which boosts performance.
  • Removes performance bugs since applications are developed into the machine code.
  • Enables to customize anything on screen regardless of its complexity.

Now let us take an overview of Kotlin along with its features and essential information. Get to know more about Kotlin in the next section.

What is Kotlin?

Kotlin is an open-source general-purpose programming language used for Java Virtual Machine. This statically typed programming language was designed by JetBrains and now Google. Since it is designed to run on Java Virtual Machine, it can also run side-by-side with Java.

Kotlin as a language is used to create Android apps in the mobile app development arena and works ONLY for Android.

What is Kotlin Muliplatform Mobile (KMM)? How is it Different from Kotlin?

Kotlin Multiplatform Mobile is an SDK designed to create cross-platform apps. With the help of KMM, developers can write the same business logic for iOS and Android apps. During app development, it helps to write the platform-specific code where necessary. The only difference between Kotlin and KMM is – Kotlin is a programming language, and KMM is an SDK.

Since KMM was released recently in 2021, it is still in the alpha phase. Still, companies like VMware, Yandex, Autodesk, and Quizlet have already started leveraging iOS and Android development because of their reusable code features.

Moreover, Philips implemented KMM to build connectivity. KMM helped the app development team to push out new features faster and write better code with less effort.

Here’s one of the tweets from an official account of Kotlin depicting how KMM helped to implement new features and served more than 1M customers.

Features of Kotlin Multiplatform

  • Lazy-loading feature to load only the required resources into the main memory.
  • Removes boilerplate code to write the code in a few lines.
  • Provides extensions for adding methods to classes without making changes in the source code.
  • By using Kotlin’s collection filtering feature, it is easy to filter the API.

So if you are looking to develop customized cross-platform apps in Kotlin, a leading mobile app development company can easily cater to your business requirements.

Let’s further discuss the detailed comparison of Kotlin vs Flutter for cross-platform development based on the features and functionalities. So have a look and decide which programming languages to choose for app development?

Looking for Cross-platform Development in Kotlin or Flutter?

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Kotlin vs Flutter: A Comprehensive Comparison

flutter vs kotlin difference

AspectsFlutterKotlin Multiplatform
SpeedIn Flutter, the app is coded fast because of the Hot Reload functionalityKMM utilizes the same codebase, libraries, and shared logic to enhance the speed
PerformanceCode is directly compiled into machine code which results in enhanced performanceApps developed with Kotlin are efficient, secured, optimal, and perform better
CommunityFlutter is launched in 2018, so it provides organized documentation and community is more compared to KotlinRecently launched in 2021, so the community is still growing and doesn’t have many resources to learn, and documentation is less organized
UI experienceFlutter offers a wide variety of widgets to design the app interface in iOS and AndroidKotlin doesn’t offer widgets to design the app. Thus, designing the app takes time
TestingIt works as Backend-as-a-Service (B-a-a-S)and provides some widget testing and app testing featuresIt provides a rich set of unit testing functionality for Android apps and doesn’t have such functionality for iOS apps
IntegrationFlutter is easy to integrate with web apps, iOS, and Android with UIKMM can only integrate business logic, and for integrating UI, it doesn’t provide constraints. Graphics designers can utilize native features
Programming languageFlutter makes the use of Dart programming language to write the same code in iOS and AndroidKotlin uses KMM SDK to utilize the same business logic on various platforms
DeveloperFlutter was developed by GoogleKotlin was developed by JetBrains and acquired by Google
Component libraryProvides an open-source repository for customizable and reusable components. Flutter’s component libraries are quickly growingAlthough it provides reusable component libraries, it is still in an early phase but growing quickly
SecurityFlutter provides a secure data storage plugin named NSUserDefault for iOS and SharedPreferences for AndroidNullPointerException is used for data security
LicenseApache License 2.0Berkeley Source Distribution (BSD) licenses
Popular appsAlibaba, Square, eBay, TencentCareem, Autodesk, Yandex, Chalk
Learning curveIt offers a comprehensive document to learn and implement FlutterKMM still has limited resources to learn the language
Access to APIPartially access to API is provided by the Flutter software development kitYes provides direct access to the latest APIs

You may have got a brief overview of the difference between Flutter and Kotlin.

Let’s understand the functionalities deeper to know what to choose for your app development project.

Kotlin vs Flutter: In-depth Difference Comparison Between Flutter and Kotlin

  1. Flutter vs Kotlin: Performance

  2. Flutter: The Flutter framework offers hot reloading functionality, which means developers can edit the code to the back-end and simultaneously observe the changes in the front-end. This decreases the need to reload the entire app frequently and saves the development and compilation time. Moreover, the code is compiled with dart virtual machines directly into the machine code, resulting in fast apps.

    Kotlin: With Kotlin, developers can set up the basic projects in less than 10 minutes. The amount of enhancement Kotlin brings in is tremendous. Moreover, Kotlin code is compiled in the same format as it is written in it. This means the Kotlin compiler is stable for both platforms. So instead of converting into another format (which takes time), it directly compiles the code, resulting in less development time.

    Winner: Draw

    Reason: In terms of performance, both Kotlin and Flutter have different functionalities and features to deliver the best performance. Kotlin’s concise code practices, improvements, extensions, support, and Flutter’s live tracking feature enhance performance.

  3. Flutter vs Kotlin: UI Experience

  4. Flutter: Since Flutter is a tool for cross-platform development, it offers a variety of widgets that help in animation, scrolling, and navigation. Thus developers can quickly and easily leverage these widgets to develop platform-specific UI. Flutter even comes with the advanced SDK for developing UI in cross-platform apps that easily fits the requirements.

    Kotlin: Its Multiplatform capability provides a free environment to create the app’s interface. It enables app developers to craft the interfaces without needing to follow constraints and instructions. Moreover, UI/UX designers can utilize native features for cross-platform applications whenever necessary or even write the platform-specific code.

    Winner: Flutter

    Reason: Since Flutter provides a variety of widgets, platform-specific designing can be quick and efficient. On the other hand, UI/UX designers take more development time in designing as Kotlin doesn’t provide the widgets and has to do platform-specific custom designing.

  5. Flutter vs Kotlin: Market Popularity

  6. Flutter framework used statistics

    Image Source: Statista

    Flutter: As per the statistics from Statista, the Flutter framework is used by 42% of developers in 2021. Moreover, companies like Google, Square, eBay, BMW have invested in Flutter to grow their businesses. It is one of the active communities having 133k stars and 19.5k forks on GitHub.

    Kotlin: Looking at the statistics from Statista, Kotlin Multiplatform is used by only 2% of the developers in 2021. Looking at GitHub, it has only got 3.5k stars and 415 forks.
    This means it is still in the growing phase. But, popular companies like Netflix, Philips, and VMware are leveraging the benefits of the Kotlin Multiplatform to scale their business.

    Winner: Flutter

    Reason: Flutter is launched in 2018, and Kotlin Multiplatform is launched in 2021 so, it is pretty obvious that the popularity and community of Kotlin Multiplatform are still progressing. However, popular companies have already adopted Kotlin Multiplatform for cross-platform mobile applications as their tech stack to grow their business.

  7. Flutter vs Kotlin: Third-party Libraries and Tools Integration

  8. Flutter: Since Flutter is cross-platform, it provides easy integration of third-party UI development tools. It integrates the platform-specific APIs for iOS and Android operating systems such as Swift, Objective C, and Java. These platform-specific languages are not dependent on code generation but make use of a flexible message-passing style.

    Kotlin: Kotlin Multiplatform operates within native platform ecosystems. You do not have to develop a code from scratch. So, developers can use the same tools and libraries like Jetpack Compose and SwiftUI that they have been using for native app development. This means they need not look for third-party tools like other programming languages to connect with the native environment.

    Winner: Kotlin

    Reason: In Kotlin Multiplatform, developers can code the projects for native apps without using third-party libraries.

  9. Flutter vs Kotlin: Programming Language

  10. Flutter: Since Flutter uses the Dart programming language, developers have to learn from scratch before developing a project in Dart. Dart is like an object-oriented programming language such as C and C++, so it is quite easy to adopt if developers are familiar with the concept.

    Kotlin: Kotlin programming language has an easy learning curve since it is quite similar to Java. Moreover, the syntax of Kotlin is pretty simple and easy and shows many similarities with the existing languages such as Swift and Java for iOS and Android, respectively. However, it is compatible with Java, but Kotlin Multiplatform offers fewer learning courses. But if developers are familiar with Kotlin, it is pretty easy to learn Kotlin Multiplatform.

    Winner: Kotlin

    Reason: Although Kotlin Multiplatform has fewer learning courses, it is pretty easy to learn. So the developers who understand Java can quickly get acquainted with Kotlin.

  11. Flutter vs Kotlin: Speed

  12. Flutter: Writing and modifying the code is a lengthy and tedious process, but Flutter will ease this task. Because one HTML code can work throughout the pages without repeating it multiple times. Moreover, constant constructors, splitting code into small widgets, and hot reload helps to increase the speed of iOS and android app development.

    With the use of constant constructors, splitting the code into small widgets, implementing lazy loading to use the data when it’s needed, and of course hot reload; helps to increase the speed of iOS and android app development.

    Kotlin: Kotlin Multiplatform facilitates faster development due to the utilization of the native components. Moreover, developers can use the same codebase, libraries, and business logic across multiple platforms. Since mobile app developers can share logic and libraries below the UI layer, they can directly interact with the native components. Apart from this, it removes a lot of boilerplate code, which results in faster development.

    Winner: Flutter

    Reason: Since Flutter offers several widgets and a hot reload feature, mobile app development in Flutter can be quick in iOS and Android.

  13. Flutter vs Kotlin: Compatibility Platforms

  14. Flutter: Flutter is designed to develop apps in Android, iOS, and desktop. Developers cannot use it for making apps on tvOS, Android Auto, CarOS, and WatchOS.

    Kotlin: There are no such restrictions and guidelines in the case of the Kotlin Multiplatform. Moreover, with Kotlin developers can develop web and mobile app projects for any device and different platforms.

    Winner: Kotlin

    Reason: It is easy to develop apps for any device. There are no constraints for any specific platforms or devices.

Flutter vs Kotlin: When to Choose?

When to Choose Flutter?

  1. If you have a small team and do not have sufficient developers to code the app in iOS and Android. With Flutter, you require only one team to code the app in both languages.
  2. If you have a simple app and it mostly depends on simple API and database calls.
  3. If you want to add custom UI like animations, navigations, and scrolling and develop a UI-specific app.
  4. Flutter is an excellent choice for developing MVP since it saves time and effort in developing the app.
  5. When you are in a hurry to release an app to the market.

When to Choose Kotlin Multiplatform Mobile?

  1. If you already have a native code or existing project and want to reuse it for another platform.
  2. If you want a native look and performance for every platform or OS.
  3. If you are not in a hurry to publish your project and don’t mind KMM being in the alpha phase.
  4. If you need minimal app designs, fewer animations, and pop-ups.

Want to Create a Cross-platform App Using Flutter?

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Let’s further understand the advantages and limitations of choosing Flutter for building cross-platform apps for your business. Understanding these will help you to make the right decision.

Advantages and Disadvantages of Using Flutter for App Development

Here are the five advantages of Flutter for mobile development:

Four Advantages of Using Flutter

  1. Reduce Debugging Time

  2. A typical application for both Android and iOS, with a similar codebase, clearly reduces the time required to debug the program for both platforms simultaneously. This results in saving time and simplifying the process of debugging.

  3. Similar App UI on Different Devices

  4. The most fantastic part about Flutter is that you can use the same user interface for both old and new devices. Apps work and look similar in different versions of Android and iOS operating systems.

    For example, an app will look identical on both the Android platform and the iOS platform. Here is an image from Android and iOS which has the same look and feel on both devices.

    Android and iOS platform

  5. Flutter Community and Support

  6. Flutter, being a new alternative compared to other cross-platform frameworks available in the IT market, had a limited number of people in the community. However, as soon as its demand increased, Flutter outperformed React Native (one of the oldest cross-platform frameworks) regarding community support and popularity. Considering the current stats, Flutter has 133,000+ stars and 19.6k forks on GitHub.

  7. Super Smooth UI for iOS and Android

  8. Smooth UI for iOS and Android

    The applications developed on Flutter have a smooth and comfortable UI as it has a Skia Graphics library. The library provides the authority to redraw the User Interface and see the changes in real-time. With the help of GPU (Graphics Processing Unit), Flutter UI offers a smooth and highly responsive experience.

  9. Perfect for MVP

  10. Apps developed by Flutter are perfect for the minimum viable product because applications are natively compiled without any interpreters or converters. It starts quickly and runs at 60 frames per second. Moreover, since the code is reused and can be developed on iOS, Android, and other platforms, development time can be saved and you can release MVP faster.

Three Disadvantages of Using Flutter

Let’s have a look at some of the disadvantages before opting for application development.

  1. Libraries

  2. The libraries of Flutter still have a long way to go. A few libraries for graphics, data fetching, and security should be added to the Flutter libraries to find them more productive.

  3. Size of the Application

  4. The application size holds significance as a large number of audiences no longer prefer heavy apps. Maybe that’s the reason Facebook and Instagram came up with a lighter version of their applications for Android users. On the other hand, Flutter apps are larger in size as compared to other alternatives. However, this issue will be resolved soon as the community is religiously dedicating a lot of time and effort for the same.

  5. Dart Language

  6. The Dart language, one of the most promising programming languages, was developed alongside Flutter. Developers are supposed to know how to use and write on Dart if they want to use Flutter. This works as a barrier and is kind of discouraging for the new developers who want to adopt a common language like Javascript if they are working on other cross-platform frameworks.

Advantages and Disadvantages of Using Kotlin Multiplatform for App Development

Four Advantages of Using Kotlin Multiplatform

  1. Shared Codebase for Business Logic

  2. With a shared codebase on Kotlin Multiplatform, Mobile developers can write the same business logic for iOS and Android. Moreover, they can write the platform-specific code where necessary.

  3. Works Well With the Existing Projects

  4. If you already have a project and want to publish it on multiple platforms, developers do not have to make it available from scratch on other platforms. It is easy for the developers to use the code and modify it to work for other platforms. However, the code migration is easy, so even if your project is complex, developers can easily integrate with KMM.

  5. Simple Syntax

  6. Kotlin is a popular programming language, and the syntax for the same is similar to other languages such as Java and Swift. If developers are aware of Java, it is easy to adopt Kotlin; the learning curve is quite less.

  7. Native UI Experience

  8. Kotlin does not require developers to work as per its own User Interface. Instead, the platform itself uses UI elements to provide the experience of native development.

Three Disadvantages of Using Kotlin Multiplatform

  1. Requires More Time to Develop

  2. Kotlin cannot be said to be the best to create a prototype or MVP quickly. The Multiplatform requires semi-native components and increases the cost of development in terms of resources and time.

  3. Still in the Developing Stage

  4. Kotlin Multi-Platform was unveiled in Kotlin 1.2. but the SDK is still in the alpha stage of development. It has some of the biggest adoptions by brands like VMware, Trikot, CashApp, and PlanGrid. However, until it gets a stable release, giants of the industry will not be completely comfortable in adopting it.

  5. Dependency on Native Components

  6. The Multiplatform uses a lot of native components with which the developers are supposed to be familiar while using Kotlin Multiplatform. Thus one cross-platform team may not be able to work on the same project. To use native components, the company may require iOS developers.

Still, have some queries regarding Flutter and Kotlin? Then, read our next section of FAQs.

FAQ About Kotlin vs Flutter

  1. How to find the React Native developers or Flutter developers to develop a cross-platform app?

  2. Here are the platforms from where you can find Kotlin and Flutter developers.

    1. Space O Canada
    2. Clutch
    3. Upwork
    4. Toptal
    5. GoodFirms
  3. How much does it cost to develop a cross-platform mobile app?

  4. The average cost of cross-platform development ranges from $15,000 to $25,000. However, it is just an average estimation of the app development cost. It varies as per the business needs, features, flexibility, and complexity of the app. So, to determine the exact cost of the application, you need to discuss your business requirements with us.

Want to Start with Flutter and Kotlin Cross-Platform Mobile App Development?

In this blog, you will get comprehensive information on developing mobile apps with Kotlin and Flutter. In addition, you have learned about the differences between Flutter and Kotlin and even get to know the information about choosing one as per the requirements. However, selecting the best framework depends on your project scale, features, complexity, and budget.

Suppose you want to kick-start with app development. In that case, you can hire a freelancer or the mobile app developers, or an experienced mobile app development team from a leading company like Space-O who has expertise in developing feature-rich apps.

We have delivered more than 300 app and web solutions across the globe for different industry verticals. Get in touch with us through the contact us form, and one of our Flutter of Kotlin consultants will get back to you shortly.

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Author Bio
Rakesh Patel
Rakesh Patel
Designation: Co-founder and CEO of Space-O Technologies

Rakesh Patel is the Founder and CEO of Space-O Technologies. He has 28 years of IT experience in business strategies, operations & information technology. He has expertise in various aspects of business like project planning, sales, and marketing, and has successfully defined flawless business models for the clients. A techie by mind and a writer at heart, he has authored two books – Enterprise Mobility: Strategy & Solutions and A Guide To Open311.