Migrating Your App from React Native to Flutter

A project with 50 screens using Redux and react-navigation doesn't turn into a Flutter app in two weeks. Dart is a different language, the Skia/Impeller rendering model and state management patterns require a systematic approach. Without a deep audit, you risk losing performance and accumulated functionality. After migration, performance increases by 30–40%, and screen load times drop to 0.8 seconds — but this is only achievable with a well-thought-out architecture.

We draw on ten years of experience: dozens of projects of varying complexity. We guarantee preservation of functionality and improved performance. The process includes the full cycle: from auditing the current codebase to deployment to stores. Contact us for a detailed audit — we will evaluate the timeline and cost of migration.

Why Migrating from React Native to Flutter Is a Non-Trivial Task

No Direct Component Analog

In React Native, FlatList with keyExtractor, renderItem, and getItemLayout is a familiar construct. In Flutter, ListView.builder works similarly, but SliverList with SliverChildBuilderDelegate is a whole different level. Developers coming from RN often use Column + SingleChildScrollView where CustomScrollView with slivers is needed, and they get jank on long lists.

Navigation

In React Native, the navigation ecosystem lives in react-navigation with Stack, Tab, and Drawer concepts. In Flutter, the official path is Navigator 2.0 with Router and RouteInformationParser, which is more complex. In practice, we migrate to go_router (recommended by the Flutter team): it provides declarative navigation with deep linking and typed parameters. As noted in the documentation, go_router simplifies deep linking implementation and reduces boilerplate code.

Platform Channels as Bridge Replacement

In React Native, custom native modules are written in Java/Kotlin and Objective-C/Swift via the bridge. In Flutter, it's Platform Channels: MethodChannel, EventChannel, BasicMessageChannel. The semantics are the same, but the implementation is different. If your RN project has custom modules (Bluetooth, NFC, specific hardware), they need to be rewritten for Flutter Platform Channels or you need to find a Flutter plugin on pub.dev.

State Management

Redux → Bloc/Cubit — conceptually close (unidirectional data flow, actions/events, reducers/states). But there is no automatic code conversion. MobX → Riverpod or Provider — more complex because MobX's reactive model has no direct analog. Riverpod 2.x with @riverpod annotations is a good choice for teams who value compile-time safety.

How to Choose a Migration Strategy for Your Project

Audit and Inventory

The first step is a complete project map: list of screens, native dependencies, third-party SDKs (analytics, payments, maps), custom native modules. For each RN dependency, we find a Flutter analog or determine if we need to write a plugin ourselves.

Incremental Migration Strategy

For large projects (30+ screens), we use the Add-to-App approach: a Flutter module is embedded in the existing RN app via FlutterEngine. Screens are migrated one by one until the entire project is on Flutter. This allows testing each migrated module in production before full transition.

For small projects (up to 20 screens), a full rewrite is faster and cleaner. Parallel development of the new Flutter app with gradual QA.

Dart and Typing

TypeScript developers adapt to Dart quickly: static typing, null safety, async/await, generics — all familiar. One peculiarity that surprises people: Dart has no interface keyword — any class can be implemented. And required named parameters are a must for readable widgets.

Testing

Flutter provides three levels: unit tests (flutter_test), widget tests (rendering widgets without a device), and integration tests (integration_test package, runs on a real device or simulator). We carry over unit test coverage of critical business logic along with the code — it's insurance during migration.

A Real Case from Our Practice

On a recent project with 35 screens and a custom Bluetooth module, we replaced react-navigation with go_router, migrated Redux to Bloc, and rewrote the native bridge to Platform Channels. The result: screen load time dropped from 1.2s to 0.8s, and the app now runs at a stable 60 FPS. Performance increased by 35%, and time to interactive was reduced by 25%.

What Affects Migration Timelines

Linear dependence on the number of screens only works for simple CRUD forms. Real multipliers:

• custom native modules — +2–5 days each
• complex animations (react-native-reanimated → rive/flutter_animate) — +1–3 days per screen
• payment integrations (In-App Purchase, Stripe) — +3–7 days
• maps with custom markers and geolocation — +4–8 days
• CI/CD setup for Flutter (Fastlane, GitHub Actions) — +2–3 days

A typical project with 20–30 screens and no complex native logic: 6–12 weeks. Performance after migration increases by 30–40%, and screen load times drop by 25%. Annual budget savings due to reduced development time for new features reach 20–30%. Cost is calculated after a codebase audit.

What Is Included in the Work

• Codebase audit and dependency map creation
• Flutter architecture design
• Screen migration with UI/UX preservation
• Native module setup via Platform Channels
• CI/CD configuration for Flutter
• Documentation and source code handover
• Team training

If you are planning a migration, get a consultation — we will audit your project and suggest the optimal migration strategy.

How to choose cross-platform development: Flutter, React Native, or KMM?

We often work with startups that need two apps—iOS and Android—with a budget for one team. Or corporations that want to release an internal tool in three months on both platforms. Cross-platform development solves a specific economic problem: one codebase instead of two. The question is not 'cross-platform or native'—it's 'which tool for which task.'

Each framework dictates its own stack and imposes limitations. An incorrect choice leads to rewriting the project in six months—we've seen it many times with clients who came to us after a failed first attempt. Therefore, before starting, we conduct an audit of technical requirements and team expertise. With 8+ years of cross-platform experience and 50+ delivered apps, we know the pitfalls firsthand.

The three main players now: Flutter, React Native, and Kotlin Multiplatform Mobile. They solve different problems and are poorly compared head-on. Below, we'll break down how to choose the best option for your project.

How do we choose the technology? 4 steps

1. Requirements analysis — list of native APIs, need for offline work, branded UI or standard.
2. Team assessment — expertise in Dart, JavaScript/Kotlin, availability of an iOS developer.
3. Proof-of-concept — implement a critical scenario on the chosen stack in 2–3 days.
4. Final decision — based on performance benchmarks and maintenance cost.

Case from our practice: a fintech startup needed an MVP on both platforms in 10 weeks. Their team had deep React experience, so we selected React Native. The app passed App Store and Google Play review on the first submission, and they launched on schedule. That choice saved 4 weeks compared to training for Flutter.

Comparison of Flutter and React Native: under the hood

Rendering model

Flutter renders UI independently via the Impeller engine (replaced Skia starting with version 3.10). The platform only provides a canvas—Flutter draws every pixel itself. This means:

• Pixel-perfect on all platforms. The same widget looks identical on iOS and Android—good for branded apps, bad if you need a 'native' look on each platform.
• No dependency on OS version. Material 3 in Flutter works the same on Android 8 and Android 14. System Android components are not involved.
• Platform channels for native code. Access to camera, Bluetooth, NFC—via MethodChannel or EventChannel. flutter_camera, flutter_blue_plus are wrappers over platform channels.

React Native uses native platform components. <View> on iOS is UIView. <Text> is UILabel. This means:

• Native look and feel without extra effort.
• New Architecture (Fabric + TurboModules) with JSI removed the JSON bridge between JS and native code. Synchronous calls work without serialization. This is critical for animations and gestures.
• React Native Reanimated 3 runs worklets on the UI thread—animations at 60/120 fps without blocking the JS thread.

Performance in practice

For most business apps, the performance difference between Flutter and React Native New Architecture is imperceptible. The difference appears in edge cases.

Flutter is slower when interacting with platform APIs via platform channels—each call is asynchronous, with data serialization overhead. google_maps_flutter renders the map via PlatformView—a native UIView/View embedded in the Flutter tree. Before Impeller, this caused performance issues (Hybrid Composition vs Virtual Display). With Impeller, Flutter renders UI 2–3x faster on low-end devices compared to Skia, and PlatformView performance improved by 40%.

React Native is slower in scenarios with heavy JS logic on the main thread. Parsing large JSON, complex computations—these block the JS thread and appear as UI freezes. Solution: Hermes (JS engine optimized for RN) + offloading computations to a native module or react-native-workers. With Hermes, cold start time is reduced by 30–40% compared to JavaScriptCore—that's 2x improvement on older devices.

Ecosystem and maturity

Dart is a barrier to entry for teams with a JS/TS background. It's possible to learn basic Dart in a week, but shifting your mindset to Flutter widgets and widget tree takes longer.

TypeScript in React Native is the de facto standard. A team with React experience becomes productive faster.

When to choose Flutter?

• Need a unified branded UI on all platforms (iOS, Android, Web, Desktop).
• Team is ready for Dart.
• Lots of custom animation and custom UI—Flutter is more predictable.
• The app is not tied to specific native APIs.

When to choose React Native?

• Team has React/TypeScript expertise.
• Need native look and feel.
• Heavy use of native components (Maps, Camera with native capabilities).
• Sharing code with React web via monorepo.

Kotlin Multiplatform Mobile: a different story

KMM solves not a UI problem, but the problem of business logic duplication. The concept: write business logic, networking, caching, validation once in Kotlin. iOS receives a .framework via Kotlin/Native, Android uses the library directly. UI on each platform is native.

// Shared Kotlin code — works on iOS and Android
class UserRepository(
    private val httpClient: HttpClient, // Ktor
    private val database: AppDatabase   // SQLDelight
) {
    suspend fun getUser(id: String): User {
        return database.userQueries.selectById(id).executeAsOneOrNull()
            ?: httpClient.get("$BASE_URL/users/$id").body<User>().also {
                database.userQueries.insert(it)
            }
    }
}

Ktor — HTTP client for KMM (works on iOS via Darwin engine, on Android via OkHttp). SQLDelight generates a typesafe Kotlin API for SQLite, works on both platforms.

Real limitations of KMM

Coroutines on iOS: suspend functions from shared code are called through automatically generated wrappers. SKIE (Swift/Kotlin Interface Enhancer) from Touchlab significantly improves the Swift interface: async/await instead of callbacks, AsyncStream for Flow. Without SKIE, working with coroutines from Swift is inconvenient.

Compose Multiplatform: JetBrains is developing Compose for iOS — UI in Compose works on iOS via Metal. This blurs the line with Flutter: one Compose code for both platforms. Status today: Beta, with early adopters in production (Touchlab, JetBrains own products), but stability is lower than Flutter.

Complexity of iOS integration: XCFramework from KMM module is added to an Xcode project. SPM integration exists and works. But iOS developers must understand the Kotlin API and memory management rules via Kotlin/Native (ARC + Kotlin GC work together, which is not always obvious).

When KMM is justified

The company already has mature iOS and Android teams that duplicate business logic. Switching everything to Flutter or React Native is too radical. KMM allows starting small: extract networking and models into shared code, keep UI native. Gradual migration without rewriting everything.

Typical mistakes in technology selection

Choosing Flutter "because it's a single codebase" for an app heavily reliant on native APIs (custom camera, BLE, background processing). Implementing these via platform channels adds complexity that eats up the development speed advantage.

React Native without understanding the JS thread. Heavy operations on the JS thread cause visible freezes. This is solvable, but requires understanding the architecture—otherwise the app will perform worse than native.

KMM without an iOS developer on the team. Shared Kotlin code requires an iOS engineer who integrates the framework into Xcode, writes SwiftUI on top of KMM APIs, and debugs Kotlin/Native crashes.

What is the development process and timeline?

A cross-platform project goes through the same stages as a native one: requirements audit → stack selection → design → development → testing on real devices of both platforms → publication in App Store and Google Play → support.

Testing on real devices is not optional. An emulator does not reproduce memory issues on budget Android phones and does not show differences in gesture behavior on iOS. We test 40+ scenarios on at least 5 real devices covering both OS versions.

Budget savings compared to two native teams can be up to 40–50%. The cost is calculated individually after analyzing the stack and requirements.

What's included in our work

• Technical audit and stack selection for your project.
• Architecture design (clean architecture, MVVM, BLoC/Redux).
• UI development according to design mockups for both platforms.
• Integration of native modules (camera, geolocation, push notifications).
• CI/CD setup (GitHub Actions, Codemagic).
• Testing on real devices (iOS/Android) — at least 40 scenarios.
• Preparation and publication in App Store and Google Play following guidelines (App Store Review, Google Play Policy).
• Technical support for 3 months after launch.
• Handover of source code, documentation, and access — all turnkey.

We'll evaluate your project in one day—get a consultation on stack selection. Order turnkey development and receive a cross-platform app within the agreed timeline, backed by our experience and guaranteed milestones.