React Native vs Kotlin Multiplatform vs Flutter: A Strategic Guide - Part 1

Table of Contents

1. Introduction: The Cross-Platform Dilemma

2. A Brief History and Where We Are Today

3. The Technology Behind Each Framework: How Do They Work?

   1. Same Difference
   2. What This Means For Startups & Teams
   3. React Native: Javascript and Native Bridge
   4. Flutter: A Custom Rendering Engine
   5. KMP: Native Business Logic, Separate UI

4. Framework Evolution And Adoption – Where Are These Frameworks Headed?

   1. Flutter: Expanding Beyond Mobile
   2. React Native: Architectural Shift with Fabric
   3. Kotlin Multiplatform: Steady Growth in Enterprise

5. Conclusion: Key Takeaways And Where To Go Next

Introduction: The Cross-Platform Dilemma

A mobile app is a must-have for almost every company today. For some, it's their primary business driver. Every organization aims to offer a seamless experience on both major platforms, iOS and Android, and sometimes try to do so relying solely on a web app. However, these organizations quickly come to the realisation that this solution often just isn't enough.

On the other hand, developing two separate apps with shared functionality is both costly and time-consuming. This is especially challenging for startups and small to medium-sized businesses that need speed and efficiency to hit their goals—whether launching an MVP, iterating to find product-market fit, or scaling up.

Cross-platform solutions like React Native, Kotlin Multiplatform (KMP), and Flutter solve this problem. Their "code once, run everywhere" approach speeds up development, reduces costs, and makes scaling easier. Even major tech companies, such as Netflix, Meta, and Google, to name a few, have embraced this strategy because of its business advantages.

The question then is: which framework should you use? The answer, as is often the case, isn't just a technical one—it's a strategic decision. This article will help you understand which solution best fits your needs and supports your business goals.

A Brief History and Where We Are Today

React Native was the first of the three to emerge in 2015. Introduced by Facebook (Meta), it quickly gained traction due to its React-based development model, making it an easy transition for front-end web developers.

A key driver of its growth is Expo, which simplifies development with a managed workflow, cloud builds, and over-the-air updates, reducing the need for complex native configurations.

With React's strong ecosystem and Expo lowering the barrier to entry, React Native now holds a 38% market share, making it one of the most widely adopted cross-platform frameworks.

Google's answer to React Native was the introduction of Flutter in 2017. Its powerful tooling and commitment to achieving near-native performance have pushed it past React Native. Over time, Flutter expanded beyond mobile to web, desktop, and embedded platforms, becoming a full-stack UI toolkit and it currently leads the cross-platform market with a 42% adoption rate.

In the same year, 2017, JetBrains, the authors of the Kotlin programming language, announced their cross-platform framework, Kotlin Multiplatform. Designed to integrate seamlessly with existing native applications, it's an attractive option for enterprises. However, since it only became production-ready in late 2023, it has a correspondingly small market share of around 2%.

The Technology Behind Each Framework: How Do They Work?

Before diving into what these frameworks are and how they work, it helps to first clarify what they are not. They are not designed to build web or hybrid mobile apps like Cordova or Ionic.

The latter rely heavily on front-end web technologies such as HTML, JavaScript, and CSS and render their content in a web browser. Although this is a legitimate attempt toward code sharing, it results in limited performance and poor overall user experience.

In contrast, the cross-platform frameworks discussed here—React Native, Kotlin Multiplatform (KMP), and Flutter—enable developers to build high-performance, native-like apps that leverage the full capabilities of the targeted OS.

Same Difference

In a fully native approach—whether on iOS or Android—the core UI components are rendered directly by the operating system, ensuring a seamless native experience with no reliance on a browser. Similarly, cross-platform frameworks aim to deliver the same level of performance and user experience as native apps.

Yet even though each framework takes a unique approach to achieving this, they all rely on the following:

• A dedicated programming language
• A specific development workflow
• A set of tools that enable deployment across multiple platforms

What This Means For Startups & Teams

Not surprisingly, these frameworks take vastly different approaches to achieving this goal, each with its own strengths and trade-offs. As a result, startups and engineering teams considering cross-platform development must carefully evaluate which framework best aligns with their objectives.

React Native: Javascript and Native Bridge

React Native is built on React, allowing developers to use JavaScript and JSX (or TypeScript and TSX) to create native mobile apps. The development process feels very similar to building a web application, making it relatively easy for front-end developers familiar with React to adopt React Native.

A core feature of React, and by extension React Native, is its declarative UI approach. Developers build applications by composing reusable UI components, making it easier to create dynamic, responsive interfaces. In React Native, these components are rendered on both iOS and Android using native UI components and APIs.

For example, a component in React Native maps to a ViewGroup on Android and to a UIView on iOS.

Moreover, beyond shared UI components, React Native enables developers to implement business logic that can be shared across platforms.

As a result, for the vast majority of apps, most functionality can be reused across platforms, with only specific cases requiring platform-specific code.

React Native previously relied on a JavaScript bridge, an intermediary that facilitated communication between JavaScript and native modules for rendering UI and executing logic. This extra step introduced overhead, leading to potential latency issues.

To address this, Meta introduced JSI (JavaScript Interface), which enables direct, synchronous communication between JavaScript and native code, significantly improving performance. With JSI, React Native no longer depends on the old bridge, but some legacy modules and third-party libraries may still use it until fully migrated to the new system.

Flutter: A Custom Rendering Engine

Similar to React Native's approach of implementing UI and business logic once and applying it across multiple platforms, Flutter achieves the same goal, but in a more unified and controlled way.

However, unlike React Native, which uses the OS's native UI elements for rendering, Flutter renders everything from scratch using its dedicated Skia rendering engine. This gives Flutter full control over how the UI looks and behaves, ensuring a consistent user experience across platforms. In a way, Flutter works more like a game engine, drawing everything itself rather than relying on platform-specific components. While this approach guarantees a uniform design, it can also make Flutter apps feel less natively integrated—certain platform-specific interactions, such as scrolling physics or keyboard behaviors, may require extra fine-tuning to match native expectations, particularly on iOS.

Flutter uses the Dart programming language to implement both UI and business logic. Since it owns the entire rendering stack, Flutter apps run incredibly close to fully native performance. This level of control allows for smooth animations, fast load times, and a highly responsive user interface. However, because Flutter does not rely on the OS's native UI components, integrating some system-specific features, especially on iOS, may require additional effort compared to React Native or fully native development.

KMP: Native Business Logic, Separate UI

Compared to React Native and Flutter, Kotlin Multiplatform (KMP) takes a fundamentally different approach. Instead of sharing both UI and business logic, KMP focuses primarily on business logic, leaving the UI to be implemented natively on each platform. This sets it apart from React Native and Flutter, which aim to unify UI development across platforms.

As the name suggests, Kotlin is the programming language used to develop shared functionality in Kotlin Multiplatform (KMP). KMP enables developers to write common business logic in Kotlin while keeping UI implementation fully native on each platform. It manages both shared and platform-specific code, allowing teams to reuse core functionality without restricting UI flexibility.

This shared code can be integrated into a native app as a dependency (or source set), enabling seamless interoperability with platform-specific APIs. With this approach, developers retain full control over the user experience on iOS and Android while benefiting from code reusability in the business layer. However, certain native interactions and OS-specific behaviors may still require platform-specific implementations.

KMP compiles to JVM bytecode for Android and native machine code for iOS. Since it doesn't rely on an extra runtime or a JavaScript bridge, KMP code runs directly on the native platform, offering better performance compared to frameworks like React Native.

Because of its modular nature, KMP can be integrated into existing apps without requiring a complete rewrite. This makes it an excellent option for companies that want to introduce cross-platform functionality gradually, rather than committing to a full migration upfront.

Note: Compose Multiplatform is not included in this article as its iOS support is still in beta at the time of writing.

Framework Evolution And Adoption – Where Are These Frameworks Headed?

When choosing a framework, it's not just about what works right now—it's about what will continue to work years down the line. Technology moves fast, and picking a framework that lacks long-term support or industry backing can lead to headaches later.

It's worth asking: Will this framework be actively maintained? Is the community growing or shrinking? Are companies betting on it for the future? These factors matter just as much as performance and developer experience.

With that in mind, here's a quick look at how each framework is positioned for the future—based on adoption, support, ecosystem growth, and long-term viability.

Flutter: Expanding Beyond Mobile

• Beyond Mobile: Flutter is no longer just a mobile framework—it's evolving into a full-stack UI solution for web, desktop, and embedded systems. With support for Windows, macOS, Linux, and even embedded devices, Flutter is positioning itself as a truly cross-platform framework that can power apps across multiple environments from a single codebase.
• Google's Commitment: Google continues to heavily invest in Flutter's multi-platform capabilities, actively improving performance, rendering efficiency, and developer tooling. With frequent updates, expanding enterprise adoption, and integration with Google's ecosystem (such as Fuchsia OS and Dart's improvements), Flutter is becoming an increasingly future-proof choice.
• Growing Adoption: Many major companies, including BMW, eBay, and Toyota, are using Flutter for their apps, signaling confidence in its longevity. The ecosystem is also growing, with an expanding package library, strong community support, and improved tooling for enterprise-level development.
• Future Outlook: Flutter is steadily transforming from a mobile-centric toolkit into a foundational layer for cross-platform development. As Google doubles down on performance, web readiness, and native integration, Flutter is poised to become a serious contender for full product UI stacks—mobile, web, desktop, and embedded. Continued enterprise adoption, ecosystem maturity, and tight coupling with Dart improvements make Flutter a compelling long-term bet, especially for startups seeking fast iteration and platform reach without compromising native performance.

React Native: Architectural Shift with Fabric

• Fabric & Hermes: A Major Performance Overhaul
  React Native is undergoing a significant transformation with Fabric, a new rendering system that improves performance, flexibility, and native integration by moving away from the JavaScript bridge model. Alongside this, Hermes, Meta's lightweight JavaScript engine, is now the default, offering faster startup times, lower memory usage, and improved execution speed, especially on lower-end devices. While these upgrades enhance efficiency, they may introduce breaking changes, requiring some adaptation for existing apps.
• Expo: Simplifying Development & Deployment. As mentioned above, Expo streamlines React Native development with a managed workflow, reducing native code dependencies. EAS (Expo Application Services) enhances deployment with cloud builds, over-the-air updates, and simplified CI/CD. With continued support for Fabric, Hermes, and platform APIs, Expo is evolving into a more powerful solution. However, fully managed projects may have limitations with custom native modules, requiring some teams to eject for greater flexibility.
• Ecosystem & Industry Adoption: Despite increasing competition from Flutter and Kotlin Multiplatform, React Native maintains a stronghold in the mobile development ecosystem, with backing from Meta and continued adoption by major companies like Microsoft, Shopify, and Tesla. Its deep integration with React and the broader JavaScript ecosystem makes it an attractive choice for web-first teams transitioning to mobile.
• Future Outlook: With Fabric, Hermes, and Expo's enhancements, React Native is becoming a more performant and accessible cross-platform solution. For teams invested in React and JavaScript, it remains a strong choice with a growing ecosystem.

Kotlin Multiplatform: Steady Growth in Enterprise

• Expanding Adoption in Enterprise: Kotlin Multiplatform (KMP) is gaining steady traction, particularly among Android-first companies and businesses with existing Kotlin-based backends. Its ability to share business logic across platforms while keeping UI layers native makes it attractive for enterprise-scale applications, where long-term maintainability and performance are priorities.
• iOS Support: While KMP provides seamless interoperability with Swift and Objective-C, its iOS tooling and ecosystem are still maturing. Unlike React Native and Flutter, which offer a more unified cross-platform experience, KMP requires additional effort to ensure full parity with native iOS development, especially when dealing with third-party dependencies and platform-specific optimizations.
• Compose Multiplatform: A Step Toward Shared UI: JetBrains is actively enhancing Compose Multiplatform, an extension of Jetpack Compose, allowing for a shared UI codebase across Android, desktop, and web. As Compose Multiplatform matures, it could significantly lower the barrier for teams looking to share UI components while maintaining native performance. However, iOS support remains in beta, and broader adoption will depend on further stability improvements.
• Future Outlook: With JetBrains' strong backing, continued improvements in iOS support, and growing adoption in enterprise settings, Kotlin Multiplatform is evolving into a pragmatic choice for companies prioritizing native UI with shared business logic. As tooling and ecosystem support expand, KMP could become a compelling alternative to fully cross-platform solutions like Flutter and React Native.

Conclusion: Key Takeaways And Where To Go Next

Final Thoughts: Cross-platform development has come a long way—not just in terms of technology, but in how companies approach building apps. It's no longer just about code reuse; it's about choosing a framework that aligns with your long-term vision.

Whether it's Kotlin Multiplatform gaining traction in enterprise environments, React Native reinventing itself with a major architectural shift, or Flutter expanding beyond mobile, each framework brings its own philosophy and strengths. The best choice isn't just about features—it's about understanding where the industry is headed and what fits your team's needs best.

As these frameworks continue to evolve, staying informed on their strengths, trade-offs, and real-world adoption will help teams make practical, future-ready decisions that align with their development goals.

In Part 2, 'll shift from the technical breakdown to the real-world business impact of choosing a cross-platform framework. I'll explore how each framework fits different industries, company growth stages, hiring needs, and long-term costs. The goal is to move past the hype and focus on practical, strategic decisions that affect your business and development roadmap. Stay tuned!