Flutter vs Kotlin Multiplatform – Choose the Best Technology for the Mobile App Project
Do you want the app development to take less time while still ensuring the product’s top-notch performance? Cross-platform technologies can make this possible.
Get to know more about Flutter, one of the most popular cross-platform frameworks, and Kotlin Multiplatform, a rising star in this field.
Read our comparison and choose the right solution for your mobile app project.
Key takeaways
- Cross-platform app development is a great way to save time and resources while ensuring top-notch performance. Two popular cross-platform frameworks to consider are Flutter and Kotlin Multiplatform.
- Cross-platform apps have a codebase that can run on multiple systems, such as Android, iOS, and even Windows or IoT platforms. This eliminates the need for separate native apps for each platform, saving time and money.
- Flutter is a favored technology for cross-platform app development. It uses a JIT compiler and Dart programming language, resulting in faster performance compared to alternatives like React Native.
- Flutter also offers special features like hot reload, which allows developers to quickly see changes in the app and make debugging easier.
- Kotlin Multiplatform (KMP) is a solution that relies on the Kotlin language. With KMP, developers can share some parts of code between platforms but not as many as in Flutter. This makes app development more time-consuming but allows for a truly native experience.
- When choosing between Flutter and Kotlin Multiplatform, consider factors like speed, native experience, and code sharing capabilities. Both frameworks offer unique advantages.
What are cross-platform apps?
Cross-platform apps have a codebase that can run on several systems, such as Android, iOS, and even Windows, Linux, or IoT platforms.
Their opposite are native apps – written, for example, in Kotlin or Swift – that we develop specifically for one platform. In practice, this means that each native app requires hiring a dedicated software developer.
There’s no such need in the case of cross-platform apps. One programmer creates a product for both Android and iOS. As a result, teams can execute their projects faster and make them more budget-friendly.
Flutter is one of the most favored technologies enabling cross-platform app development. But you don’t have to choose between Flutter and native solutions. Kotlin Multiplatform has recently become a note-worthy alternative for those who want to cut some time on the mobile app development process but also care a lot about native experiences.
Let’s delve deeper into the differences between them.
What is Flutter?
It is a software development kit that enables sharing large parts of code between multiple platforms.
Flutter’s main alternative is React Native, but some reports show that its popularity is gradually declining. Why? Mostly because Flutter is faster. It uses a JIT compiler and a Dart programming language that doesn’t communicate with native elements via a bridge.
Hot reload is another unique functionality of Flutter. Software developers use it to see what the app looks like immediately after they make changes to the code. It allows them to quickly check if their work produces the desired results and also makes debugging easier.
App examples
ABOUT YOU
It’s an eCommerce app that previously was built in React Native. This technology didn’t allow the team to develop the product as fast as they needed, so they made the decision to switch to Flutter.
Read more about this project.
Source: Google Play Store
Wolt
Wolt chose Flutter for simple reasons: They wanted to save time and use fewer resources than when maintaining two codebases for iOS and Android. A cross-platform app was the best solution. Additionally, Flutter enables the creation of responsive designs and facilitates integrating native features.
Check out the case study about this app.
Source: Google Play Store
LeggUP
LeggUP is a platform for personal and professional development. At first, there was only a web solution, but the team needed a dedicated mobile app to allow users to contact their coaches quickly. That’s why features like live chat are available. On a mobile app, users can also quickly find materials for their courses.
Read more about this project.
Source: Google Play Store
What is Kotlin Multiplatform?
Although Kotlin Multiplatform (KMP) also enables building apps for many different platforms, this technology is a whole different solution than Flutter. It relies on the Kotlin language, the same one we use at Holdapp for the native Android app development.
With KMP, you can share some parts of code between Android and iOS, web, and desktop, although not as many as in Flutter. The latter enables you to build one UI for iOS and Android apps, whereas with KMP, developers must create it separately for each platform.
It makes app development more time-consuming. On the bright side, it allows you to create user interfaces that provide a truly native experience.
App examples
Forbes
This news app uses Kotlin Multiplatform, allowing Forbes to publish features on iOS and Android simultaneously. Over 80% of business logic is shared across two mobile platforms, which speeds up the implementation of new elements.
Read the article about Forbes’ transition to KMP.
Source: Google Play Store
PowerSchool (formerly Chalk)
PowerSchool apps offer tools that support teachers. Its team uses KMP to share business logic, networking, and online caching between platforms. The shift from fully native apps to Kotlin Multiplatform enabled faster feature development and testing.
Get to know the details behind this transition from this interview.
Source: Google Play Store
Unflow
Unflow is a CMS dedicated to mobile apps. Its team says Kotlin Multiplatform enabled them to implement some complex features without as much effort as it would have to be required for two native apps.
Source: Google Play Store
Read more about KMP app examples.
Comparison: Flutter vs Kotlin Multiplatform
| Flutter | Kotlin Multiplatform | |
|---|---|---|
| Basic info | Google's open-source technology | JetBrains' open-source technology |
| Programming language | Dart | Kotlin |
| Language's popularity | Although Dart is intuitive and easy to learn, it's less popular than Kotlin and is rarely helpful in projects that don't involve Flutter. | Kotlin is considered a perfect language for beginners. For years, it's also been a must for Android developers who program native apps. That's why it's easier to find experienced Kotlin developers than specialists in Dart. |
| The stable version launch | 2018 | 2023 |
| Platforms |
|
|
| App development time | It's faster than native technologies and even Kotlin Multiplatform because you can share more parts of code between Android and iOS applications. Many ready-to-implement UI components also speed up the app development process. | The mobile app development process takes less time than in the case of native apps because you can share parts of code between platforms. When sharing business logic, you also cut the time on double testing it. However, developing Flutter apps should still be faster than KMP because you also build one UI layer for two platforms. |
| App development cost | Building a Flutter app costs less than developing two native apps, although not by half. QA testing still must be performed on two platforms. | KMP app development requires less budget than two native apps but more than one Flutter app. That's because you can easily share Flutter's UI across Android and iOS. KMP apps, on the other hand, offer platform-specific UI. |
| UI development | There are customizable widgets to build UI in Flutter. Apps can look more native, thanks to dedicated libraries. There's Cupertino for iOS and Material for Android. | KMP offers the Compose Multiplatform framework, which enables the sharing of UI implementations across Android and desktop apps but not on iOS or the web. As a result, in KMP apps, UI is developed separately for each platform, thus providing a native experience. |
| Quick preview after changes | Flutter has a hot reload feature, so when developers add changes to code, they immediately check how they affect the app. They also see whether something needs fixing. | KMP doesn’t provide an option to quickly check the changes on the UI. |
| Libraries | There are many big libraries that offer customizable, pre-built widgets, although it's important to stress that developers can also build their own widgets. For example, to create animations, change layout and styling, or improve accessibility. Adding integrations for notifications or cameras isn't challenging either, even without using native elements. | The number of libraries is smaller compared to native ones or Flutter, but the good news is that it's continuously growing. |
| Flexibility | It enables building simple MVPs and much more complex apps. You can build an app entirely in Flutter or just add Flutter elements to native apps. It's helpful if you want to shift to cross-platform technology gradually. It works the other way around, too. You can add native elements to Flutter apps. It comes in handy when you need to implement new platform-specific features that haven't been adjusted to Flutter yet. | You can gradually transition from native code to KMP. Start by choosing priorities and decide which parts of the code should be rewritten first. |
| Performance | Flutter apps compile directly into native code without a bridge, which allows them to run faster. Their graphic engine, Impeller, enables quick animation rendering and ensures stability. | Kotlin code is compiled directly into the native code for each platform. This way, it ensures fast performance. |
| Documentation | Flutter is well-documented, especially regarding the UI layer, so finding information should be easy in most cases. | Currently, KMP documentation is somewhat limited due to the fact that it's still a new technology. |
| Community support | Flutter's community is quite big and still growing. It accelerates the growth of this technology and makes it easier to find help. Developers can ask questions on forums or join Flutter's Slack, Reddit, or Discord channels. In many cities, events for Flutter developers take place. | KMP developers can find info on Slack channels for Kotlin and join discussions on Kotlin forums. |
Flutter vs Kotlin Multiplatform: what should you choose?
As you can see in the table above, both solutions have their pros and cons. Here’s a summary to help you choose the technology for your project.
#1 In what cases should you consider Flutter?
- When you want to build the app for two platforms as soon as possible.
Why Flutter? It allows sharing the largest part of code compared to KMP. It also offers a hot reload feature, enabling developers to check changes faster and fix bugs at an earlier project stage.
- If you want to offer complex or unique features.
Why Flutter? It is a more mature technology that offers many pre-built widgets with clearly written documentation. It also brings together a bigger community, which helps with complicated projects.
- When you need to minimize the cost spent on the app development project.
Why Flutter? This cross-platform technology allows you to spend less budget on writing code. Instead of hiring two native app developers, you work with one Flutter developer.
#2 When is it best to choose Kotlin Multiplatform?
- If you already work with a team that knows your project well and specializes in natively developed apps.
Why KMP? Learning Kotlin Multiplatform will be much easier for them. Plus, they already know your brand and understand your project goals, so you don’t have to spend extra time explaining the guidelines and cooperation principles to them.
- If it’s essential to ensure platform-specific UI and provide native experiences to Android and iOS users.
Why KMP? Shared business logic in Kotlin can be easily combined with natively coded UI for two platforms. As a result, people can enjoy solutions they are used to, which improves their experience.
Remember that every project should be analyzed individually. It’s always better to consult experienced software developers about the technology choice. At Holdapp, we can recommend the best cross-platform development solution based on your project requirements. Get in touch if you need any help.
