React Native vs. Flutter: the key differences every developer should know in 2021

The world of cross-platform development is tearing between the two most popular frameworks - React Native and Flutter. According to recent research, in 2021, React Native and Flutter have the support of the majority of developers. Besides, Flutter’s popularity has been increasing since 2019 while React Native has been losing it.

However, the statistics don’t mean that the time of React Native passed and the framework lost its relevance. Instead, it continues to evolve its capabilities and remains an indispensable tool for cross-platform development.

But you are here to find out which is the best: mature and stable React Native or rapidly growing and performant Flutter. Thus, without further ado, let’s do it. In this article:

• General information on RN and Flutter;
• The comparison of the frameworks by the several performance metrics;
• Pros and Cons of Flutter and React Native;
• RN and Flutter use cases with applications examples.

React Native and Flutter the essence

React Native

React Native is a free and open-source framework for developing mobile, web, desktop & other cross-platform applications. But in contrast to Flutter, the performance is much better with the web apps.

The Facebook team released it in 2015, and it has much hype from the start. Its impressive tools set and performance brought the framework popularity and the devoted community of contributors. At present, Rect Native offers even more development capabilities and evolves into complete platform agnosticism, bridge simplification, and streaming model upgrade.

React Native uses React web development framework as a basis. RN uses JavaScript, TypeScript, and JSX programming languages basis which makes the platform easy to use for the majority of developers. React Native controls native rendering through Objective C/ Swift on iOS and Java/Kotlin on Android. React Native works with components to render the app natively on various platforms. The components are the substitutes of widgets. They are easy-to-use but look not as natively and aesthetic as the widgets.

Flutter

Flutter is a Software Development Kit (SDK) for cross-platform development. Similar to React Native it is free, open-source, and allows developers to create all kinds of applications (mobile, desktop, various types of web apps, and more).

Google presented Flutter in 2018 as a beta version. Then, in 2019, after stabilizing the APIs and improving the system in line with the users’ feedback, the team announced Flutter 1.7. Since that time, the Flutter community has been growing rapidly.

Flutter uses the Dart client-optimized programming language. Like Flutter, it was created by Google especially for fast and complex applications. Dart is written with JavaScript and resembles it in a lot of ways. The language will be easy to learn for developers who have experience with JavaScript and C#. Apart from the language, Flutter's widgets enhance the rendering performance and cross-platform capabilities of the platform.

React Native vs. Flutter: the ultimate battle

In this section, we will compare performance metrics and features of the two frameworks.

Architecture

In terms of architecture, React Native and Flutter have much in common. Flutter has similar structural elements except for the Bridge and the programming language. It makes the performance of Flutter applications better than React Native ones.

As we said, React Native has a slightly more complex structure than Flutter. Also, it includes some unique structural elements like JS input. With RN, you can use multiple UI/code frameworks, libraries (Ignite CLI, Native Base, UI Kitten), and native modules to streamline the development process.

Winner: Flutter

Community

The community is a vital factor for a cross-platform development framework. One way or another, you will encounter issues you won’t be able to resolve by yourself. What’s more, the popularity makes it easier to find an experienced and creative developer to create your app. In such cases, you can reach out to the community and get the support you need.

Despite the Flutter’s young age and fledgling status, it has a mature community. Additionally, there are quite a lot of open libraries where you can find various functionalities. It would be fair to say that these libraries don’t contain all the functionalities you might need for your application. Thus, you’ll have to create them by yourself. But, the extension of the libraries is just a matter of time for the Flutter team and contributors.

The Flutter community grows rapidly but doesn’t catch up with React Native’s level of support. RN is three years older than Flutter and had its time to gather up a significant group of contributors and fans. Moreover, it has been dominating the cross-platform development area until 2021. So, there’s no surprise that React Native has a stable community and comprehensive knowledge base. Besides, RN offers an unprecedented number of ready-made functionalities and component libraries.

Winner: React Native

Code reusability

With Flutter, you can build iOS and Android apps using a single codebase throughout iOS, Android, Windows, macOS, Linux. Also, you can create web apps for Firebase, Chrome, Safari, and Edge. Apart from that Flutter apps can be embedded with TV sets, cars, and smart home devices. However, sharing code in web environments can be quite challenging, considering the overall weak performance of Flutter there.

Out-of-box you can reuse RN code across iOS and Android devices. However, with the help of special libraries, you can apply the single code to the same platforms as Flutter.

Another way you can share the RN code is to inject it as a dependency. To do that, you need to extract the code you share and to a separate repository and treat it as a separate project.

The method allows developers to focus on the development of a platform-specific application without any concerns about compatibility with other platforms.

Winner: Draw

Performance

As both RN and Flutter work in several different environments, we will compare their performance in each of them.

Mobile

Flutter performs various kinds of tasks much faster than React Native. This difference boils down to the architecture of the platforms. React Native has the Bridge element that takes its time and resources to translate the JS code into native platform-specific languages.

At the same time, Flutter doesn’t need any additional interlayers. It takes load from a device and streamlines the application performance. Also, Flutter has a powerful C++ visual engine that makes the rendering of mobile apps seamless and detailed.

Winner: Flutter

Web

So as React Native is based on React web development platform, it dominates the web application development field. In addition, RN uses JavaScript which straightens the front-end side of its web applications. React Native suits for the development of all kinds of web applications:

• PWAs (Powerful Web Applications) that have the capabilities of a desktop app.

• SPAs (single page apps) that load once and transmit the info from the internet services to the app and vice versa.
  On the other hand, Flutter’s Dart programming language is rarely used for web applications development. So, Flutter web application development capability is more of a nice-to-have feature. Still, Flutter web applications can be quite performant and fast.

Winner: React Native

Desktop

React Native desktop applications perform slightly better than Flutter. For example, an RN app can generate random DNA sequences only in two seconds and consume 71 kb of operational memory. In contrast, it would take 6 seconds and 159 kb to execute the same operation.

Winner: React Native

Application UI & Styles

Widgets and Dart UI capabilities win the game for Flutter in the rendering competition. They are based on material design and give developers more freedom of expression in UI development. Further, the Flutter applications will look the same on the newest and older devices. Flutter mobile apps look more like hybrid applications made in Ionic or Xmarin than native.

React Native uses platform-specific graphic blocks to build UIs. It uses JavaScript and React instead of native languages (Java, Swift, Kotlin, etc.) Besides, React Native employs Virtual Dom instead of using Web Views to render the interfaces. It enhances the rendering performance, optimizes a device’s memory usage, and makes an application lighter. Virtual DOM is especially useful for web applications rendering. And, finally, React Native uses native UI components so they update together with the iOS/Android app without any delay.

Eventually, both platforms are capable of pixel-perfect and seamless UI rendering. Flutters’ lack of native look is compensated with the vast styling features. At the same time, React Native’s native look and performance are slightly overshadowed by the lack of style variety.

Winner: Draw

Testing

With React Native and Flutter, developers can reduce testing time by half. It is possible because QA specialists can run the same test on two mobile platforms. Although, the applications for both platforms should be identical. In other words, the more similarities between the applications, the less testing they require.

React Native supports the IDE software suite, which opens wide testing automation capabilities. So, developers can choose from Espresso, Jasmine, KIF, Appium, Calabash, UI Automation, Robotium, Frank, TestNG, and more. The weakness of React Native application testing is that you won’t have any support or documentation for the testing routines.

Flutter testing has three categories: integration testing, unit testing, and widget testing. As opposed to RN, all three categories of testing have the support and detailed documentation. Dart programming language is great for non-UI testing because it runs on your development hardware. Also, Dart has vast testing automation features and tools like IDE (debugging), DartDevTools, and Continuous Integration (CI).

Winner: Draw

React Native Pros and Cons

Pros

• Open-source and free-to-use;
• You can access platform-specific APIs asynchronously;
• High development speed due to the code-sharing, components reusability, and hot reload feature;
• Flexible code;
• You can build apps for multiple platforms;
• Strong developer community with thousands of contributors that expand the framework’s feature set and provide support;
• 3d party libraries support pre-made code patterns;
• Exceptional UI rendering capabilities with the help of Virtual DOM without using WebViews;

• Native controls that facilitate the development process.
  Cons

• RN developers may need native platform knowledge to solve more specific tasks;

• May require additional infrastructure to maintain complex applications;

• Debugging can be challenging.

Flutter Pros and Cons

Pros

• Fast coding process with hot reload feature;
• Vast code-sharing capabilities;
• Flutter apps are very fast and performant;
• Ambitious and rapidly growing community;
• Aesthetic designs on all kinds of devices;
• Very low time-to-market;
• Rich UIs due to the programming language;
• Works with all platforms and devices.

Cons

• Relatively small community;
• Functional libraries and support aren’t complete because of the young age of the platform;
• Weak performance in web environments.

When to Use Flutter and React Native

Flutter

Opt for Flutter in the following cases:

• You’d like to create a platform-specific design for your application;
• You need an extremely fast and performant application;
• You are ready to create some functionalities for your app by yourself;
• You want to create the instant and small-sized app;

Google Ads app

Google ads mobile app helps managers track their advertisement campaigns on the go. The functions of the application are:

• Real-time performance summaries and notifications;
• Ad campaigns management;
• Monitor advertisement performance any time anywhere.

eBay Motors

This application helps car owners and vendors to sell their vehicles right from their smartphones. It allows users to:

• To pay for the cars from the application due to the payment systems integration;
• Arrange shipping of the vehicle;
• Have message/voice negotiations;
• Uploading the photos of the vehicle and the related documentation.

Philips Hue

The app allows users to control the light in their room. To perform its functions the application includes:

• Bluetooth to connect with the Philips illumination devices;
• Integration with a device’s microphone for voice lightning control;
• Light change timer for special moments and times of the day.

React Native

React Native perfectly suits you in the following cases:

• You want to build your MVP at short notice. With React Native, it will take only several weeks;
• You are counting on the community support during your app development;
• You need easy access to platforms’ hardware functionality without 3d party plugins;
• You’d like to use the app in the web environment too;
• Your app requires complex controls and operations.

Facebook

Unsurprisingly, the company demonstrated the capabilities of its framework, creating Facebook social media mobile app for Android and iOS. Among the application’s features are:

• Text/voice messaging, video chats, and phone calls;
• Location tracking through GPS;
• Photo, video, music cloud storage.

Walmart

The largest retailer in the US, Walmart, entrusted its mobile app to the React Native developers. They’ve created a functional app capable of:

• Integrated chat-bot for customer support;
• GEO-positioning of goods and customers for delivering them;
• Price scanner and medical prescriptions management.

Instagram

The world’s best photo/video-sharing platform is also made with React Native. The app has:

• The ability to connect with smartphone’s camera, record stories, make photos, period and record videos;
• Capacious and high-performant cloud storage;
• Text chat, collaboration tools, real-time photo/video content editing.

Conclusion

Now, it’s time to summarize all the facts about the frameworks and decide which application is better. It's up to you and the choice depends on your application requirements. Both React Native and Flutter can give birth to performant and rather fast cross-platform applications for different devices. Both of them offer cool features like hot/live reload that enhance the development process and have exceptional UI rendering capabilities.

However, the frameworks differ in structure, cross-platform development approaches, programming languages, and the capacity for design and styling.

Hope this comparison helped you to choose the appropriate cross-platform framework for your new application. Good luck!

P.S. If you still have questions or want to delegate your cross-platform development to a solid and experienced team of developers, contact us. Akveo provides the full cycle of services including app development, UI/UX & web design, branding, quality assurance, and technology consulting.