Flutter and React Native Bridge Architecture Guide (1).pdf

In the ever-evolving landscape of mobile app development, cross-platform frameworks have gained popularity for their ability to build applications that run seamlessly on multiple platforms. Two prominent players in this space are Flutter and React Native. While they offer similar advantages, the way they bridge between native and non-native code varies.

1. Flutter and React Native Bridge Architecture Guide



In the ever-evolving landscape of mobile app development, cross-platform frameworks
have gained popularity for their ability to build applications that run seamlessly on
multiple platforms. Two prominent players in this space are Flutter and React Native.
While they offer similar advantages, the way they bridge between native and non-native
code varies. In this blog, we will explore the ways of bridging these cross-platform technologies.
How is Flutter's Bridge Architecture?

2. Flutter’s bridge architecture is designed to enable smooth communication between the
Dart code and the native code of Android or iOS.
1. Flutter uses Platform Channels
At the core, Flutter uses Platform Channels, a mechanism that acts like a two-way
communication tunnel. Platform Channels are like a telephone line between Flutter’s
Dart code and the native parts of the phone (like Android or iOS).
Imagine your Flutter app wants to use the camera. Dart (Flutter's language) doesn't
know how to do that directly. So, it sends a message through the Platform Channel to
the native system (like Android’s Java or iOS’s Swift).
The native system does the job (like opening the camera) and sends back the result
through the same channel. It’s a way to talk between two different languages — Dart
and the phone’s native language.
2. Dart code sends messages to the native side

3. Through this tunnel, the Dart code sends messages to the native side when it needs
platform-specific functionality — such as accessing the camera or GPS — and receives
responses in return.
This means the communication goes both ways, like a conversation between two
people. Dart code can ask native code to do something (like get battery level). Native
code can also send back information to Dart. So, it’s not just one side sending
commands, both can talk and listen. That is the reason why it’s called a two-way tunnel.
3. Flutter compiles Dart into native ARM code
Unlike other frameworks, Flutter compiles Dart into native ARM code ahead of time,
which allows for faster performance and less reliance on the bridge during runtime.
Phones use processors (like your computer’s CPU), and most smartphones use an
ARM processor. Dart, the language Flutter uses, is converted into native machine code
that ARM processors understand, before the app runs. This is called Ahead-of-Time
(AOT) Compilation. Because this step is done in advance, the app runs faster and
smoother, just like a native app. Think of it like translating a speech before a conference, so there’s no delay during the
event. It makes the app feel more responsive and professional.
The Flutter Engine, written in C++, also plays a key role in managing rendering and
communication. This architecture is beneficial because it keeps the app experience
smooth, reduces lag, and makes it easier to use native features — all while using a
single codebase.
How is React Native's Bridge Architecture?

4. 1. React Native Bridge Connects JS Code with Native APIs
React Native’s bridge architecture connects JavaScript code with the native APIs of
Android and iOS. This bridge works asynchronously — meaning JavaScript sends a
message to the native layer, the native system processes it, and then sends a response
back. This back-and-forth happens through a dedicated "bridge" layer, which serializes
the data into a format both sides can understand. It means the communication between JavaScript and native code doesn’t happen
instantly or block the app from running while waiting for a response. Instead, the app
sends a message through the bridge, keeps running, and gets the response later when
it's ready.
For example:
Think of sending a WhatsApp message:
●​You type the message and hit send.
●​It’s sent to the server while you keep chatting or switch to another conversation.

5. ●​Later, you see the double tick once it’s delivered.
That’s how asynchronous communication works, your app doesn’t wait around doing
nothing. It sends the task, moves on, and handles the result later when it’s ready.
2. React Native Use Native Modules
To access native functionalities, React Native uses Native Modules — small pieces of
native code written in Java (Android) or Objective-C/Swift (iOS). These modules can be
called from JavaScript when device-specific actions are needed.
3. Use batch Calls & Background Threads for Heavy Tasks
While this architecture offers flexibility, it can lead to performance issues if too many
messages cross the bridge frequently. To avoid this, developers often batch calls
(Instead of sending many small messages one by one, developers group them together
and send them all at once) and use background threads (doing the heavy work silently
in the background so the app stays smooth) for heavy tasks. Overall, React Native’s bridge makes it possible to build apps using JavaScript while still
tapping into powerful native features.
Common Challenges and Best Practices:
Framework Best Practice

6. Flutter
(Performance
Considerations)
●​Dart-to-Native Communication: Reduce the
frequency of method calls between Dart and native
code. Batch calls when possible to avoid unnecessary
overhead.
●​Platform Channels: Leverage asynchronous methods
to avoid blocking the UI thread during communication
with native code.
●​Method Channel: Optimize data serialization between
Dart and native code. Use efficient serialization
methods, especially when dealing with large datasets.
React Native
(Performance
Considerations)
●​JavaScript-to-Native Communication: Minimize the
data passed between JavaScript and native code.
Batch calls and transfer only essential information.
●​Native Modules: Write efficient native modules to
ensure that the execution of platform-specific
functionality is as performant as possible.
●​Native Module: Consider using background threads
for time-consuming tasks in native modules to prevent
blocking the main thread
Flutter & React
Native (Additional
Performance
Considerations)
●​UI Rendering: In both Flutter and React Native, use
native UI components whenever possible to ensure
optimal rendering performance.
●​Dispose Resources Properly: In Flutter, use dispose
methods to release resources, and in React Native,
handle memory management carefully to avoid
memory leaks.

7. ●​Debugging Performance Issues: Both Flutter and
React Native provide tools for performance profiling.
Use these tools to identify and address performance
bottlenecks.
Flutter & React
Native (Error
Handling)
●​Consistent Error Reporting: Ensure consistency in
the format of error messages or objects returned from
native code. This makes it easier to handle errors
uniformly in the Dart or JavaScript code.
●​Logging Errors: Implement robust logging
mechanisms to capture errors during development and
testing. This helps in diagnosing issues during the
debugging phase.
●​User-Friendly Messages: When appropriate, provide
user-friendly error messages or notifications to inform
users about issues encountered during the
application's execution.
Building Mobile Solutions That Solve Real-World
Challenges
Looking to build a mobile app that runs seamlessly across Android and iOS? Whether
your goal is to streamline internal operations, boost user engagement, or ensure
smooth integration with device features, choosing the right cross-platform approach is
key.
At Synoverge, we have partnered with businesses across industries to solve these very
challenges using technologies like Flutter, React Native, and other modern frameworks.
Our customer success stories showcase how organizations have achieved scalable

8. performance, secure deployments, and faster time-to-market; all through smart,
future-ready mobile solutions delivered by Synoverge.
Explore Synoverge case studies and see how we can help you build high-performing,
cross-platform mobile apps that deliver real business impact.
Conclusion
Bridging in cross-platform mobile app development technologies like Flutter and React
Native plays a crucial role in achieving an integration of native and non-native code.
Understanding the underlying mechanisms and best practices for bridging is essential
for developers aiming to deliver high-performance, feature-rich applications across
multiple platforms. As the mobile development landscape continues to evolve,
mastering the art of bridging becomes a valuable skill for cross-platform developers.
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