FLUTTER VS KOTLIN MULTIPLATFROM APP DEVELOPMENT: THE 2025 GUIDE TO CROSS-PLATFORM APP DEVELOPMENT

Intro

Building a cross-platform app saves you time and money since you only write one codebase for multiple platforms. It’s a cost-effective way to speed up development and launch faster.

Now comes the big question: which cross-platform framework is best for you? The one you pick will affect how fast you build, how much you spend, and how smooth the app runs on both iOS and Android.

1.

WHAT IS FLUTTER?

Google launched Flutter in 2017, and it’s become a go-to choice for many businesses since then. By the end of 2024, 28% of new apps in the iOS App Store were built with Flutter.

1. BUSINESS LOGIC PLUS UI

Flutter handles both the business logic and UI in one unified codebase. Flutter mobile app developers build the UI and logic once, then deploy it across iOS, Android, web, and desktop. This ensures your app looks and works the same everywhere. But while this is great for fast development, it might not always give you the highest level of customization.

2. USING OWN TOOLS FOR UI

Flutter engineers say, “Never say no to your designer,” and that sums it up. The whole idea behind it is that Flutter gives designers exactly what they need — a pixel-perfect design that looks great, no matter the platform. 

Flutter has its own UI tools to deliver a great UI without platform-specific adjustments.

• Ready-made, tested widgets for iOS and Android. Yes, they’re not technically native, but they perform and behave in a native-like way.
• Hot reload for instant UI updates without restarting the app.
• A custom rendering engine (previously Skia, now Impeller) that handles UI, animations, and effects independently of Android/iOS. This means a consistent look across platforms and faster performance.

Flutter makes development faster by using its own tools instead of native ones. But since it doesn’t rely on platform-native components, the performance might not always match a fully native UI.

3. BRIDGES FOR API ACCESS

Because Flutter uses Dart, a universal language, it doesn’t directly interact with iOS and Android’s features. Instead, it relies on a bridge to translate Dart code into native platform code. This extra step is typically not an issue, but for complex apps, it may be slower than fully native development.

2.

POPULAR USE CASES FOR FLUTTER

ECOMMERCE AND MARKETPLACE APPS

Flutter is perfect for e-commerce apps. With a single codebase, it works seamlessly on iOS, Android, and the web. It offers pre-built widgets for product grids and shopping carts, saving you time. Plus, it handles real-time updates smoothly, like stock levels and order statuses.

DESIGN AND CREATIVITY APPS

For photo editing and design apps, Flutter’s pixel-perfect UI lets you create smooth, responsive layouts for things like image editing and design tools. 

ENTERTAINMENT APPS

If you’re making entertainment or social networking apps, Flutter’s high-performance rendering ensures everything runs smoothly. You can deliver rich, interactive content while keeping everything in sync across platforms, and the fast iteration lets you test and update your app quickly.

Want more Flutter use cases? Check out our blog, where Touchlane’s Lead Mobile Developer shares his insights.

3.

REAL-WORLD APPS BUILT WITH FLUTTER

• Google Ads. Millions of businesses use Google Ads, and Flutter makes sure the app runs smoothly on both iOS and Android.
• BMW. BMW uses Flutter to deliver the same great experience on iOS and Android with one codebase. Features like hot reload ensure fast development and a reliable app for users.
• Alibaba. With over 800 million users, Alibaba uses Flutter to keep the shopping experience fast and reliable across platforms.
• Reflectly. The AI-based journaling app was built by just 2 engineers in only 2.5 months using Flutter.
• eBay. eBay uses Flutter to keep their app running smoothly, even with millions of buyers, sellers, and real-time transactions.

1.

WHAT IS KOTLIN MULTIPLATFORM (KMP)?

Kotlin Multiplatform (KMP) comes from Kotlin, a language made by JetBrains as a simpler alternative to Java. Kotlin became the main choice for Android, and KMP takes that a step further by letting you build cross-platform apps.

1. BUSINESS LOGIC, NO UI

Kotlin Multiplatform (KMP) focuses on sharing business logic, leaving the UI separate. In contrast, Flutter ties business logic and UI together, making it harder to separate them. With KMP, you can easily share core logic across iOS, web, desktop, macOS, and even watchOS. That’s why KMP saves time on business logic, but UI needs to be handled separately.

2. USING NATIVE TOOLS FOR UI

Unlike Flutter, KMP doesn’t have its own UI tools. Instead, it relies on each platform’s native tools. While this helps your app look and feel more native, it also means you need to build and maintain separate UIs for each platform. This can take more time and add complexity to the development process.

JetBrains is working on making UI development easier with Compose Multiplatform (CMP). It’s designed to let you share UI code across platforms. However, as of early 2025, CMP is still in beta for iOS and alpha for the web, so it’s not fully stable yet.

3. DIRECT API ACCESS

With KMP, you write your business logic in Kotlin, and KMP compiles it into native code for each platform (Android, iOS, web, etc.), no extra layers or bridges needed. Whether you’re working with Android or iOS, you can just import the code and start using platform-specific features right away. This makes development smoother and faster.

2.

POPULAR USE CASES FOR KOTLIN MULTIPLATFORM

APPS REQUIRING A NATIVE LOOK AND FEEL 

Some apps, like streaming, banking, or health tracking, need to feel native on each platform to meet user expectations and integrate seamlessly with the system. With KMP, you can keep the UI for each platform while sharing the same core logic across them.

APPS WITH COMPLEX BUSINESS LOGIC

KMP helps reduce repetitive code by sharing core logic, like workflows, calculations, and payments, across platforms. This makes it easier to maintain and update multiple features. It also reduces errors and keeps everything consistent.

TRANSITION FROM KOTLIN ANDROID

If you already have a Kotlin Android app or work with Android developers, KMP lets you reuse business logic across iOS, web, and desktop, while keeping your Android UI. This way, you can add KMP gradually, avoiding a complete rewrite and reducing the risks of big changes.

3.

REAL-WORLD APPS BUILT WITH KOTLIN MULTIPLATFORM

• Netflix. Netflix uses Kotlin Multiplatform to share business logic across platforms while maintaining a native-like experience for its users.
• McDonald’s. McDonald’s has separate iOS and Android apps with complex logic. They’ve created a KMP module as a shared library, which both platforms use. This allows the company to share business logic while keeping the native UIs.
• Cash App. The finance app has developed Redwood, its own library that helps build the same UI across Android, iOS, and web using shared code. 
• Trello. The project management tool also uses Kotlin Multiplatform to share core business logic across platforms. This improves productivity and speeds up cross-platform performance.
• Pinterest. Pinterest uses KMP to create a smooth experience on both Android and iOS. 

KOTLIN MULTIPLATFROM VS FLUTTER, 2025: KEY CONSIDERATIONS AND OVERVIEW

DEVELOPMENT PHILOSOPHY

For Flutter, everything is shared — both business logic and UI, all written once. The upside: faster, cheaper development. The downside: sometimes the look and feel may differ between iOS and Android. For some apps, this doesn’t matter, but for others it can be essential.

KMP focuses on sharing business logic. But for the UI, you’ll need to use native tools. This approach has pros and cons. On the plus side, KMP apps don’t just feel native — they are native, because the UI is built with each platform’s native tools, just like a traditional mobile app. This requires more time and effort, but it’s worth it for apps where UX/UI is crucial. 

PERFORMANCE COMPARISON 

KMP is great for apps that need native performance, especially those with complex business logic. It works directly with the platform’s APIs, so it’s perfect for an app where performance is a top priority.

Flutter, on the other hand, uses its own rendering engine and a bridge to access iOS and Android features, which means it offers near-native performance. Yet, Flutter is a solid option in most cases, especially if you need an app with great UIs and quick updates.

UI/UX CAPABILITIES

Flutter focuses on UI-first, offering pre-designed widgets for consistent, beautiful UIs across platforms. However, you might need some tweaks for platform-specific designs.

KMP doesn’t prioritize UI sharing (except with Compose Multiplatform). Developers build separate UIs for each platform, which means more work but full design flexibility.

CODE REUSABILITY AND SHARING

Flutter lets you reuse both business logic and UI across platforms with one codebase for iOS, Android, Web, and desktop.

KMP, on the other hand, only shares business logic, while requiring separate UIs for each platform.

COMMUNITY AND ECOSYSTEM SUPPORT

Flutter has a large community and strong support from Google. This means plenty of first-party and third-party libraries, plugins, and tools are available, making development faster and easier.

KMP, backed by JetBrains, also has a growing fanbase, particularly among Kotlin/Android developers. Google now officially supports KMP, and while the library selection is smaller compared to Flutter, it’s expanding quickly.

SO, FLUTTER VS KOTLIN MULTIPLATFORM? PERFORMANCE AND MORE TO CONSIDER

PROJECT TYPE AND REQUIREMENTS

Need a single codebase for everything? Go with Flutter. Want to keep the native feel but share core logic? KMP is the better fit.

TEAM EXPERTISE

If your team knows Kotlin, KMP will be an easy transition. If you want a smoother learning curve and faster setup, Flutter’s pre-built tools make it a solid choice.

SCALABILITY AND MAINTENANCE

KMP shares logic while letting each platform have its own UI. Flutter’s single codebase is easier to manage but may need extra tweaks to feel fully native.

TIME-TO-MARKET VS CUSTOMIZATION

Flutter helps you launch fast with ready-to-use widgets. KMP takes more effort but gives you full control over the UI on each platform.

CASE STUDIES

Now, let’s check in more detail how developers and businesses benefit from Flutter’s and KMP’s benefits in real life. 

1.

REAL-LIFE EXAMPLE OF FLUTTER APP DEVELOPMENT: SMARTVOLT 

SmartVolt, a startup in energy management, needed a working app fast — just three months to lock in funding. The app would help users control electricity use, track energy consumption, and cut heating costs.

They brought in Touchlane for our Flutter mobile app development skills and flexibility. Flutter allowed us to build fast without cutting corners. Having one shared codebase, we could focus on domain-specific details that made the app stand out: real-time energy tracking, electricity prices, and weather forecast, all seamlessly integrated.

As a result, SmartVolt launched on time, secured funding, and is now getting ready for a bigger release next season.

2.

REAL-LIFE EXAMPLE OF KOTLIN MULTIPLATFORM APP DEVELOPMENT: TV5UNIS

TV5Unis is a Canadian streaming service available on multiple platforms. The goal was simple — make sure viewers could watch their TV shows, movies, and more on any device, whether it’s mobile, web, tvOS, or Amazon Fire TV. That’s why a multiplatform approach made perfect sense.

So, why Kotlin Multiplatform? Because KMP allowed the developers to write core logic once and use it everywhere. At the same time, they could customize the user interface for each platform. This way, the app looked and worked the same on all devices, giving users a great experience.

Conclusion

In 2025, both Flutter and KMP are solid choices for cross-platform app development, and they each have exciting plans for the future. It’s not about which one is better overall — it’s about which one works best for your specific needs.

WHEN TO CHOOSE FLUTTER

• You want to use one codebase for both UI and business logic, making development faster and testing easier.
• You want to speed things up with a lot of pre-built widgets, packages and plugins, so you can quickly add features without having to build them from scratch.
• You need a consistent design across platforms and don’t need the UI to match the native look exactly.

WHEN TO CHOOSE KOTLIN MULTIPLATFORM

• You want to share the core logic between Android and iOS but still keep the native feel on each platform.
• You’re working on apps with a lot of business logic, like complex rules, calculations, and workflows, and want to reuse code to save time and effort.
• You already use Kotlin on Android and want to quickly extend your code to iOS.

At Touchlane, we’re experts in cross-platform app development and ready to help you succeed. Share your Flutter app idea with us, and we’ll get in touch to talk through the details.