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React Native Integration with Brownfield development

Integrate cross-platform features with native apps maintaining their business continuity 

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Callstack made the perfect staff augmentation partner. Their engineers were well versed in all things React Native and proved to be a crucial part of our mobile app relaunch project.

Brian Aznar
Engineering Director of Major League Soccer

How does it work?

Implement the same React Native feature into multiple native apps simultaneously illustration


Implement the same React Native feature into multiple native apps simultaneously

Implement new cross-platform React Native features to multiple native apps only once - they will work on all the platforms.

The stages of the process:


Two native versions of the same app (Android and iOS) work separately.
No code shared. There are two separate codebases and teams.


The cross-platform feature is written in React - a JavaScript framework. Then React Native generates an interface for native platforms.


The feature created with React Native is being injected into both apps at the same time working side by side with the native code. No need to rewrite the entire native application to start sharing the code.


The common cross-platform feature is developed and maintained by a single team. There’s no longer a large panel of experts involved.

Gradual transition of native apps into cross-platform illustration


Gradual transition of native apps into cross-platform

Transform multiple native apps into one, cross-platform React Native solution gradually, feature by feature. Without rewriting the app from scratch.
Integrate new components into a working app and replace its existing native pieces one by one.

The stages of the process:


Two native versions of the same app work separately.


Subsequent elements of these apps are being gradually rewritten with React Native and some pieces of native code.


Two native versions of one app become one cross-platform app that can be developed and maintained by one team.

Feature parity on all your platforms illustration


Feature parity on all your platforms

A common cross-platform React Native feature works the same on all platforms without differences in performance.

The stages of the process:


A specific feature doesn’t work the same on two native versions of one app. 


By transforming this feature to React Native, it becomes a common cross-platform element of two native apps.


Despite the different platforms (Android, iOS, etc.), the feature works the same on each of them.

Brownfield software development advantages

icon Code sharing

Code sharing

Write code once and run it everywhere. While React Native makes the features work properly on every platform, you can focus on improving the product.

icon Feature parity

Feature parity

Don’t disappoint your users with missing or inconsistent platform-specific features. Integrate and launch cross-platform features into multiple native apps at the same time.

icon Gradual improvement

Gradual improvement

Instead of writing a new app from scratch, incrementally replace platform-specific features with cross-platform ones. Validate the approach and nail out the technical details before going all in.

Business benefits

The advantages of Brownfield software development

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Costs reduction

Hire one team for Android and iOS and reuse native code to reduce costs up to 50%

icon Inclusive applications

Inclusive applications

Provide your customers with inclusive apps that work the same on every platform

icon Better time efficiency
Better time efficiency

Reuse existing native code, but expand the app in JavaScript

icon Live and OTA Updates
Live and OTA Updates

Add features and  updates without going through the app store update cycle


Why should you opt for cross-platform solutions?

We talk a lot about moving from native apps to React Native apps that work on every platform. But how is the React Native integration better from your current native solutions?

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icon Write once, run everywhere

Write once, run everywhere

Once built, React Native apps can work on iOS, Android, Windows, tvOS, and more

icon Faster development process

Faster development process

Interfaces are composed of smaller building blocks, which reduces the code duplication

icon Less coding and faster time-to-market
Less coding and faster time-to-market

Less coding means less time needed to launch an app

Need to integrate React Native features into existing apps?

Estimate project

Real-life examples

More and more companies decide to use Brownfield development in their apps. Check out how they benefit from integrating React Native in existing applications.

Created a performant cross-platform app with components shared across the stack.
Outcomes and business benefits:

A highly performant cross-platform application that shares the components across the stack

 Meeting a tight deadline for the project due to applying a time-efficient technology

project preview
Developed a fast-loading app with a native feeling on both iOS and Android.
Outcomes and business benefits:

Improved navigation for both Android and iOS.
Native code can be reused in React Native keeping a native feeling of the application on every platform.
Everything is in one repository with the React Native version in sync.

project preview

Learn more about React Native Integration

Learn more about about the benefits and use cases of Brownfield software development by visiting our blog and reading below articles:

blog coverread article
blog coverread article

React Native Brownfield Library

The library contains our best practices and tools that we pick when adding React Native to existing projects.

Currently, we are working on a new version of the library in order to reduce the steps needed to set up React Native in a Brownfield environment to a bare minimum.

Github logo

To stay on top of the updates,
be sure you watch the repository on Github.

How do we work?

We offer flexible solutions adjusted to your needs. Our process is crafted to fit small and enterprise clients.

We join your team, dive into your project and tell you what we can do together. Our partnership model of collaboration can be broken down into six steps:

How it looks in practice


Initial call

We set up an initial call to understand your application and learn about the issues you have.



Based on the initial call, we prepare a proposal and assign you a developer that best suits your needs in terms of skills and knowledge.


Research phase

We become your team members to learn everything about your project and organization. We join your meetings, chat with your programmers to look at the project from your perspective.


Pair-programming and knowledge sharing

We cooperate with your developers on your project and share our knowledge with them at the same time. 


Report with measurable improvements

At the end of the first month, we present you a report with our recommendations based on the research described in Step 3.You decide if you want to continue the cooperation or implement what we recommend yourself.


Further cooperation and support

Once you decide to continue the cooperation, we will implement the recommendations and support your further efforts. We will be happy to guide you through your next steps. You can always count on our expertise.

Why work with us?

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Experienced in working on demanding React & React Native projects

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Creators and maintainers of many Open Source libraries used by millions

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Core Contributors to React Native and official Facebook partners

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Organizers of the biggest React Native conference - React Native EU

I would have no hesitation in recommending Callstack to others, to provide a flexible solution to an existing workforce or on a longer-term basis as part of a remote team.

Ben Caulfield
CEO & Co-founder @ Eedi


Let's work together!

Need help with React or React Native? Let us know!

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