Cross-Platform App Development: Flutter vs React Native vs Kotlin

2025-09-12 • RedSun IT Services

Cross-platform app development lets teams write one codebase that runs on multiple platforms. By 2025, the leading frameworks are Flutter (Google’s UI toolkit), React Native (Meta’s JavaScript/React platform), and Kotlin Multiplatform (JetBrains’ cross-platform SDK).

A 2024 survey found roughly 9.4% of developers using Flutter and 9.0% using React Native, showing wide adoption. Each framework aims to speed mobile delivery while avoiding duplicate coding for Android and iOS. Let’s explore them.

Flutter

Flutter is Google’s open-source UI toolkit for building natively compiled apps from one codebase. It launched in 2017, and its first stable Android/iOS release came by 2018; later updates added web and desktop support. Recently (Aug 2024), Flutter 3.24 introduced a low‑level GPU API and multi‑view rendering for richer UIs, reflecting its rapid evolution. Key advantages include:

Advantages:

• Fast UI development Flutter’s “Hot Reload” lets developers instantly see code changes. It uses a rich widget library, so UIs are consistent across platforms.
• High performance via ahead-of-time compilation and the Skia graphics engine.
• Unified design with consistent UIs across platforms.

Real-world use: Google Pay India, Alibaba, BMW.

Drawbacks: Learning Dart, larger app sizes, and a steeper learning curve for teams moving from web/native.

React Native

React Native (RN), created by Meta in 2015, uses JavaScript and React to build mobile apps.

Advantages:

• Familiar technology for web/React developers.
• Native rendering for a natural Android/iOS feel.
• Large ecosystem with npm libraries, Expo, and community plug-ins.

Real-world use: Facebook, Instagram, Tesla.

Drawbacks: Some performance issues due to the JS bridge, though improvements like the Hermes engine and new architecture reduce these gaps.

Kotlin Multiplatform

Kotlin Multiplatform (KMP), developed by JetBrains, allows shared business logic across Android, iOS, and more. Unlike Flutter or RN, it’s not a full UI toolkit.

Advantages:

• Code sharing for business logic, networking, and data models.
• Native UI with SwiftUI or Jetpack Compose.
• Easy adoption for Android teams already using Kotlin.

Real-world use: Netflix, Cash App, 9GAG.

Drawbacks: Smaller ecosystem, experimental modules, and the need to write some platform-specific UI code.

Conclusion

In 2025, cross-platform app development offers mature options:

• Flutter → Best for rich, custom UIs and high-performance apps.
• React Native → Great for JavaScript/React teams and faster iteration.
• Kotlin Multiplatform → Ideal for Kotlin-centric teams seeking near-native performance.

All three frameworks continue evolving, so the best choice depends on your project needs and team expertise.

Need help deciding? Contact RedSun IT Services — we optimize your mobile app workflows with the right tools and strategies.