Flutter vs React Native: What To Choose in 2021

Krunal Shah

Jan 27, 2021 | 9 min read

flutter vs react native

It’s 2021 and there is a great urgency for businesses to carve out space for themselves in the mobile phones of their users. Regardless of the industry, every business wants to create a quick mobile app in order to offer a comprehensive and customized solution to individual customers. Unfortunately though, creating native apps for Android and iOS are quite time-consuming, and hence, cost-intensive. So the concept of cross-platform development has gained momentum and Flutter vs React Native has become the community’s favorite buzzword.

Cross-platform apps are faster to develop because they let you use the same code for multiple platforms. However, different frameworks offer different features and advantages for efficient cross-platform development.

In this blog, I have tried to present a detailed comparison between the two most popular cross-platform frameworks - Flutter and React Native.

Table of Contents

What is Flutter?


Flutter is a reactive cross-platform mobile development framework that uses the Dart language.

Dart and Flutter have been created by Google who’s using the framework for some of its biggest applications.

Naturally, they are constantly pushing the framework towards being the ultimate solution for creating cross-platform apps. Its initial alpha release was back in May 2017 so it’s much younger than React Native.

What is React Native?

React Native

React Native is perhaps the renowned world champion of cross-platform mobile development. React Native is a javascript framework built upon the React library, both created by Facebook, and it allows you to ship IOS and Android apps with a single code base.

It’s used primarily by Facebook, Instagram, Airbnb, and many others. React Native started out as an internal hackathon project at Facebook back in 2013, and in 2015 it was released to the public.

Top features and advantages of using Flutter for cross-platform development

advantages of flutter

Codesharing leading to faster development

Like any other cross-platform technology, Flutter allows you to use the same code base for building separate iOS and Android apps.

This, in turn, speeds up the whole development process and means that you don’t need two teams working on the code for a single platform.

Easy bug fixing with Hot Reload

Flutter’s “hot reload” makes it possible to make changes to the code and see the results immediately in the app preview, without the need to recompile the code.

This way, you can easily fix bugs and experiment with different UI elements and features once you’re at it.

The layered architecture enables high customization

Flutter has a layered architecture that paves the way for easy and quick UI customization. It’s said to give you control over every pixel on the screen” and let you overlay & animate graphics, video, text, and controls without limits.

Clear separation of UI from the native controls

Flutter separates UI from native controls, which eliminates a lot of nuances and errors made by smartphone manufacturers.

These might not happen too often but are difficult to omit with native development. Separate UI also means having a unified view on all system versions without an effort.

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Top features and advantages of using React Native for cross-platform development

top react native advantages

Rich components library reduces manual development time

The major selling point of React Native is the shorter development time. The framework provides numerous ready-to-apply components that can accelerate the process.

React Native is based on JavaScript, which gives access to the largest package ecosystem in the world. Having access to such an extensive base of packages, you can save much time, and it will only get better.

Fast Refresh is a step ahead of Hot Reloading

One of the top React Native pain points was that the Hot Reload feature was broken. Most developers had it turned off as it was unreliable. The response to these complaints is Fast Refresh.

This tool, released at the end of 2019, fixes all the issues that Hot Reloading has and provides a great developer experience that speeds up both building new features and bug fixing.

Declarative UI

React Native is solidly based on creating a mobile UI. In native development, you will need to create a sequence of actions in the application.

React Native employs declarative programming in which such an order of implementing actions is obsolete. As a result, it is much easier to spot bugs on the paths a user can take.

Strong community support

If a React Native developer experiences a problem, they can turn to the vast community for support (as of Jan 2021, there are nearly 93000 active contributors to the React Native tag on Stack Overflow).

There will always be someone who’ll be able to help them resolve their issues – this also has a positive impact on improving coding skills.

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Flutter vs React Native: Technology Architecture

React Native requires JavaScript Bridge as a run time environment for the app to function. This bridge serves as a medium for JS code to communicate with native modules.

In simple words, React Native mandates the JS code to be compiled into native code at run time. You need to use JSON to enable this communication between the two sides.

Thus, if the app isn’t built with a smooth UI, there are high chances of increased load time for the UI elements. That’s because the rendering speed of each UI element is heavily influenced by the performance of the JS bridge.

React Native uses Facebook’s Flux architecture to build smooth, fast-performing mobile apps.

Because Flutter uses Dart, it gets the advantage of having access to the Dart’s in-built tools for UI.

For example, it comes packed with design tools like Material Design (for Android) and Cupertino (for iOS) that are quite resourceful for building mobile apps. It uses the Skia engine to leverage the power of these built-in tools.

Thus, Flutter app architecture is pretty simple to work with. There is no need for any mediator (like JS bridge) because Dart and Skia compile the native code ahead of time.

In short, the Flutter engine comes with pretty much everything required to build cross-platform mobile apps.

Now let’s compare the two frameworks side by side, on important considerations

React Native vs flutter app development

Each framework has its own pros and cons but those alone are not sufficient to help us make the right choice. So here’s a side by side comparison of Flutter vs React Native on all the important considerations of mobile app development.

Flutter vs React Native: Performance

This one builds on the previous point.

React Native has to rely on JavaScript Bridge to communicate with native components. So obviously, it takes more time to load the elements. On the other hand, Flutter compiles the code ahead of app run time. So the performance is much, much faster in Flutter apps.

That means, your Flutter app can yield animation runtime speed of as high as 60 frames per second.

But, I am not saying that kind of speed is not possible to produce in React Native apps. You can certainly use third-party libraries that provide the same app speed. However, there are always more complications with the app the more libraries you integrate it with, especially when you build hybrid apps.

Undoubtedly then, Flutter is a clear winner when it comes to building high performing hybrid mobile apps!

Flutter vs React Native: Testing Support

Again, because Flutter uses Dart, it offers comprehensive support for automation testing. Flutter developers and testers have access to tons of testing features for unit, integrated, and widget testing of the app.

The cherry on the cake is Flutter’s detailed documentation for making the most of its testing features. The documentation also helps you with automated app releases on both Play Store and App Store.

On the other hand, React Native has absolutely zero official testing support for UI level and integrated testing. The tools that it does offer is only for unit testing and that’s a very limited set too.

That means, React Native developers have to rely on third-party tools like Appium and Detox for UI level testing.

Furthermore, there is no support for automated app deployment on Play Store or App Store either. You have to work your way through Xcode/Android Studio to manually deploy the app to their respective stores.

Flutter vs React Native: Code Maintainability

In React Native, upgrading and debugging the code can be a pain. When you fork the code to suit your application, it interferes with the framework’s logic thereby slowing down the development process.

In addition to that, most of the native components might have a third-party library dependency. Often these libraries are outdated and cannot be maintained properly due to the issues that come along with it by default.

In contrast, maintaining a Flutter application is much easier. The simplicity of code helps developers spot issues, source external tools, and support third-party libraries.

Furthermore, the time taken for releasing quality updates and making immediate changes in the application are considered to be better in Flutter than the hot reloading capacity of React Native.

Flutter vs React Native: Developer Productivity

If the React Native developer is skilled in JavaScript, then it’s fairly easy to use those skills for cross-platform app development. React Native has a hot reload feature which saves a lot of developer time while testing the changes in the UI.

In terms of IDE support, developers are free to use any text editor or IDE of their choice.

Flutter also has a hot reload feature and it’s very easy to get started with the demo app.

However, as the complexity of apps grows, developers would need to learn and adopt the new Flutter concepts. In addition, Dart is not a common programming language and there is a lack of support for it in many IDEs and text editors.


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When to choose React Native and when to use Flutter?

Before I dive into when to choose what, take a look at some of the popular apps built with Flutter vs React Native. That alone will give you an idea as to which one is suitable for which kind of app.

flutter and react native

React Native is a good framework to build simple native and cross-platform applications, and Flutter does a great job at creating multiple iterations and MVP applications.

Choose React Native, if:

  • You want to scale your existing applications with cross-platform modules.
  • Your requirement is to develop lightweight native applications.
  • You are looking for possibilities to create shared APIs out of the box.
  • Your goal is to create an application with an asynchronous build and a highly responsive UI.
  • You have sufficient time and money to invest in the project.

Choose Flutter, if:

  • Your idea does not require complete native functionality.
  • The budget and delivery timeline are tight.
  • You want to write codes faster and deploy them into the market quickly.
  • You are aiming at creating applications that perform at a speed between 60 FPS and 120 FPS.
  • You requirement is to customize UI with widgets and less testing.

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Krunal Shah

Krunal Shah is the CTO and Co-founder at Third Rock Techkno. With extensive experience gained over a decade, Krunal helps his clients build software solutions that stand out in the industry and are lighter on the pocket.

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