As a mobile app developer with over 10 years of experience testing apps on real devices, I often get asked – which is better for cross-platform app development, Flutter or React Native?
Both Flutter and React Native allow you to build mobile apps that run on both iOS and Android using a single codebase. This saves significant time and effort compared to building native apps separately for each platform.
However, Flutter and React Native have some important technical differences that you should understand before choosing one for your next app project. In this in-depth guide, we’ll compare Flutter vs React Native across 10 key factors:
1. Programming Languages
Flutter apps are written in Dart, a language developed by Google specifically for building user interfaces. Dart is an object-oriented language that has features similar to JavaScript and Java.
React Native apps are written in JavaScript and use the React framework for the view layer. Many developers already know JavaScript, so React Native may have a lower learning curve. However, Dart is also relatively easy to learn for an experienced developer.
2. Technical Architecture
Flutter uses its own high-performance rendering engine to draw widgets and interface elements. This avoids the need for JavaScript bridging required by React Native. It compiles all the way down to native ARM code for excellent performance.
React Native uses JavaScript bridge to enable communication between UI components and native platform APIs. This architecture can have performance limitations, but React Native team is making improvements here with frameworks like Fabric.
3. UI Development and APIs
Flutter has a rich set of customizable widgets for building mobile app UI. It doesn’t rely on native OEM widgets. The widget set is also consistent across both iOS and Android.
React Native uses native UI components instead of reinventing them. This can make the UI feel more consistent with other apps on that platform. However, UI components behave differently on iOS vs Android.
As far as external APIs, React Native has wider support as JavaScript is more common for native APIs. Flutter can access native SDKs through platform channels.
4. Developer Productivity
Flutter’s hot reload feature helps accelerate development by allowing you to quickly view UI changes without restarting your app. Developers can experiment faster to build the best UI.
React Native also offers fast refresh through hot reloading. But view layer code changes are still slower to see than Flutter’s sub-second hot reload. Flutter’s consistency in UI framework across iOS and Android also improves productivity.
5 Language Popularity for Hiring
While Dart has gained popularity since the launch of Flutter, JavaScript is still much more widely used by developers. If your team is already proficient in JavaScript, or if you need to hire cross-platform developers, React Native may make it easier.
However, many developers are adopting Flutter given its momentum. So you can build a skilled Flutter team, it just may take more effort currently than finding React Native developers.
6. Stability and Support
React Native is more mature, having been released in 2015. It has time-tested stability with its JavaScript-based framework and comprehensive support from the open source community.
As the newer framework launched in 2017, Flutter support continues to evolve. Google developers are actively maintaining and enhancing Flutter, so its stability and capability improve with each release.
7. Performance
Apps built with Flutter tend to have better performance overall. Its compiled code avoids the need for a JavaScript bridge. Testing indicates Flutter apps can launch and run faster, with smoother scrolling and animations.
React Native has introduced integrations to help close this performance gap. For example, the Fabric framework for React Native allows it to get closer to native performance for large lists and table views.
8. App Size
Flutter application packages are larger in size because the Flutter engine is bundled with each app. For an average app, this adds between 3 and 7 MB.
React Native app sizes are generally smaller since they only include the UI layer code along with required JavaScript libraries like React. The app then runs on the native platform and OS frameworks already available on the device.
9. Code Reuse for Multiplatform
A key benefit of cross-platform app frameworks is being able to reuse code across platforms. Both Flutter and React Native excel here, but with an additional exciting capability for Flutter.
Flutter apps don’t just run on mobile. With additional web support introduced in Flutter 1.12, you can reuse Flutter code to publish web apps or desktop apps for macOS and Windows. This gives Flutter a cross-platform advantage.
10. Testing Framework and Tools
Flutter has robust integrated testing support including unit, integration, performance, and UI tests. These testing components help validate performance, catches bugs early, and facilitates test automation workflows.
React Native relies on common open source test runners like Jest for unit testing, with additional UI layers tested using frameworks like Detox. There is wider tool support as JavaScript testing is more mature.
