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React Native App Development Agency — UK

React Native
for real products.
Not just shared code.

Wall & Fifth builds production iOS and Android applications with React Native, Expo and TypeScript. The goal is not to maximise code sharing at any cost — it is to create a maintainable mobile architecture with the right balance of shared product logic and platform-specific behaviour.

React Native architecture
React + TypeScript product layer
UI · state · navigation · API integration · product logic
React Native + native modules
iOS
Native platform
Android
Native platform

What React Native is

It is not a
website in an app.

React Native lets developers build mobile interfaces and application logic using React and TypeScript while integrating with the underlying iOS and Android platforms.

It is different from placing a responsive website inside a mobile shell. React Native applications use platform-native UI capabilities and can call into native modules when the product needs functionality that sits closer to the device.

The practical advantage is architectural: large parts of the product can be maintained together without pretending that iOS and Android never need different implementations.

Shared code

The useful question is not
“how much can we share?”

It is “what should be shared, and what should remain platform-specific?”

Product logic
Usually shared
API integration
Usually shared
Authentication flows
Usually shared
State management
Usually shared
Navigation structure
Largely shared
Design system
Largely shared
Push configuration
Platform-aware
Permissions
Platform-aware
Store configuration
Platform-specific
Certain device APIs
Platform-specific when required

React Native + Expo

What Expo
adds to the stack.

Expo provides tooling, libraries and configuration around React Native development. It removes a lot of repetitive platform setup and provides established integrations for common mobile capabilities.

That does not mean the product is confined to a toy environment. Native projects and modules can still be used when the application requires deeper platform-specific work.

We use the toolchain because it can reduce unnecessary implementation work while keeping the architecture open to the native capabilities a production app actually needs.

Native capabilities

Shared architecture does not mean
giving up the device.

Notifications

Push and product messaging.

Camera & media

Capture, uploads and media access.

Location

Maps and location-aware product behaviour.

Biometrics

Device-supported secure authentication.

Device APIs

Platform capabilities where required.

Native modules

Native implementation for specialist requirements.

Store releases

Separate iOS and Android production builds.

Platform fixes

Platform-specific behaviour isolated when needed.

React Native vs Swift + Kotlin

One mobile architecture
versus two independent ones.

React Native

Shared product core

Much of the application maintained together
Shared React and TypeScript expertise
Platform-specific code where justified
One core feature implementation in many cases
Strong fit for many product-led applications
Separate native

Swift + Kotlin

Separate iOS and Android application code
Maximum direct platform control
Useful when the product is heavily native-specific
More duplicated product implementation
Two technical surfaces to maintain
Read the full cross-platform architecture guide

The decision

When React Native is
the right engineering choice.

Strong fit
Marketplaces
Social and community products
Booking applications
SaaS companion apps
Transactional mobile products
Membership and content applications
Products targeting iOS and Android
Consider fully native
Graphics-intensive games
Extremely low-level hardware interaction
Products dominated by native-only frameworks
Very unusual performance constraints
Products where iOS and Android are intentionally different systems

Performance

Performance is an
architecture problem.

“Is React Native fast enough?” is too broad a question. Performance depends on what the application does, how the UI is structured, how much work happens on each thread, how data is loaded and whether specialist work is moved into native code where necessary.

For many SaaS, marketplace, social, transactional and service-based mobile products, React Native is a practical production architecture. Products with very unusual graphics or hardware requirements deserve a more specific technical decision.

That is why we choose the architecture around the product rather than selling React Native as a universal answer.

After launch

The maintenance advantage is
as important as the first build.

Shared feature work

Many product changes can be implemented in the shared application layer rather than independently recreated twice.

One core architecture

A smaller technical surface can be easier to understand, extend and onboard developers into.

Explicit platform differences

iOS- and Android-specific code can remain isolated instead of contaminating the shared product layer.

React Native pricing

Define the product.
Then fix the scope.

Focused React Native appfrom £16,000

A tightly scoped production mobile product using React Native, Expo and the integrations required for launch.

Extensive React Native appfrom £30,000

A larger mobile system with multiple user types, richer workflows, deeper integrations or broader operational requirements.

Read the app development cost guide

React Native FAQ

Technical questions
before you commit.

Wall & Fifth is a London-based software and product development studio building production mobile applications with React Native, Expo and TypeScript. Work can cover product strategy, UX/UI, mobile engineering, backend integrations, testing and release preparation.

React Native is a framework for building mobile applications with React and JavaScript or TypeScript while rendering through native platform components. It allows substantial parts of an iOS and Android application to share code while still supporting platform-specific implementations where required.

No. React Native is not simply a website displayed inside a WebView. The application uses React Native components that interact with the underlying iOS and Android platforms, and native modules can be used when platform-specific capabilities are required.

Expo provides tooling and libraries around React Native development, including common device capabilities, build workflows and application configuration. It can reduce unnecessary setup while still allowing native functionality and platform-specific work where the product requires it.

Yes. React Native applications can integrate with device capabilities including notifications, camera, location, biometrics, media, payments and authentication. The implementation depends on the product and the native APIs involved.

A dedicated native approach can be more appropriate when a product depends heavily on unusual platform-specific frameworks, very low-level hardware interaction, intensive graphics or workloads where the architecture is dominated by native platform code.

Focused Wall & Fifth React Native builds start from £16,000. Larger products with multiple user types, complex workflows, substantial integrations or broader operational requirements typically start from £30,000.

Yes. The finished React Native codebase and associated intellectual property are handed over to the client. There is no proprietary app-builder licence or requirement to remain with Wall & Fifth.

Related mobile expertise

React Native sits inside
the wider app architecture.

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Build one product.
Respect both platforms.

We'll help decide whether React Native is right for the product, what should be shared and where native platform work is actually justified.

Book a scoping call