Last month, our internal dashboard tool—originally built on Electron—hit a critical ceiling. On a standard corporate laptop (8GB RAM, Windows 11), the application was idling at 650MB of memory usage. This wasn't a complex video editor; it was a glorified log viewer with real-time WebSocket updates. Users complained about fan noise and sluggish system performance whenever they kept the app open in the background. We faced a decision: spend weeks optimizing the Chromium render process or evaluate Flutter for its compiled native performance. This article documents our migration experiment, the architectural friction points we encountered, and the raw benchmark numbers that surprised the entire engineering team.
The Core Bottleneck: Chromium vs Skia
To understand why we saw such a disparity, we have to look below the syntax. Electron essentially bundles a dedicated instance of Chromium and Node.js with every application. When you render a list of 10,000 logs in Electron, you are manipulating the DOM. Every <div> has overhead—style calculation, layout reflow, and paint composition. Even with virtualization libraries like `react-window`, the memory footprint baseline is massive because the V8 engine and the browser context must be loaded into memory.
In contrast, Flutter takes a radically different approach. It bypasses the native OS UI widgets and the web DOM entirely. Instead, it uses the Skia (or the newer Impeller) graphics engine to draw every pixel directly to a canvas. This architecture eliminates the heavy bridge required to translate JavaScript calls into native UI commands. For our log viewer, this meant that rendering text was just a rasterization command, not a DOM tree mutation.
The "Naive" IPC Mistake
One of our early failures in the Electron version was how we handled data ingestion. We were passing large JSON blobs from the Main Process (Node.js) to the Renderer Process (React) via Context Bridge. This requires serialization and deserialization across the IPC boundary.
Here is the legacy code that caused UI stutters during high-traffic bursts:
// ELECTRON (Legacy Implementation)
// main.js
const { ipcMain } = require('electron');
ipcMain.on('stream-logs', (event, data) => {
// MISTAKE: Sending huge objects creates GC pressure
// Serialization cost here blocked the event loop
mainWindow.webContents.send('new-logs', JSON.stringify(data));
});
// preload.js
contextBridge.exposeInMainWorld('api', {
onLogs: (callback) => ipcRenderer.on('new-logs', callback)
});The serialization cost of JSON.stringify on megabytes of data repeatedly froze the UI. In Flutter, because the UI and the logic run in Dart (which compiles to native ARM64/x64 machine code), we share memory much more efficiently. We utilize Dart Isolates for processing, which can pass memory references or structured binary messages without the heavy JSON serialization tax found in JS interop.
The Optimized Flutter Approach
Migrating to Flutter allowed us to leverage FFI (Foreign Function Interface) for the heavy lifting if needed, but pure Dart proved sufficient. The key win was the Impeller rendering engine. It precompiles shaders, eliminating the "jank" often associated with first-run animations on other platforms. Below is how we structured the stream listener in Dart to avoid blocking the main UI thread.
// FLUTTER (Optimized)
// log_service.dart
import 'dart:isolate';
void spawnLogListener(SendPort sendPort) {
// This runs in a separate thread (Isolate)
// No locking the UI Main Thread
final rawSocket = connectToSocket();
rawSocket.listen((data) {
// Process binary data directly
final parsed = parseBinaryLogs(data);
sendPort.send(parsed);
});
}
class LogViewer extends StatefulWidget {
@override
void initState() {
super.initState();
final receivePort = ReceivePort();
// Spawning a lightweight isolate
Isolate.spawn(spawnLogListener, receivePort.sendPort);
receivePort.listen((message) {
setState(() {
// Direct state update, Impeller handles the paint
logs.add(message);
});
});
}
}Notice the simplicity. We aren't fighting an IPC bridge or worrying about the serialization format. The data flows from the background isolate to the UI isolate seamlessly. Because Dart is strongly typed and AOT compiled, the memory layout of the Log object is known at compile time, reducing runtime overhead significantly compared to V8's dynamic object allocation.
2025 Benchmark Results: RAM & Disk Size
We ran both the optimized Electron build (v33) and the Flutter build (v3.27) on the same MacBook Pro M3 Max and a mid-range Windows Dell Latitude. The application functionality was identical: Connect to a WebSocket, buffer 50,000 log lines, and render a virtualized list.
| Metric | Electron (React) | Flutter (Desktop) | Difference |
|---|---|---|---|
| Idle RAM Usage | 180 MB | 42 MB | Flutter uses ~76% less RAM |
| Heavy Load RAM (50k items) | 650 MB | 110 MB | Massive scaling difference |
| Installer Size (macOS) | 145 MB | 38 MB | Chromium bundle vs Native Binary |
| Cold Startup Time | 1.8s | 0.4s | Instant vs Browser Boot |
The numbers speak for themselves. The RAM usage difference is not just an optimization; it's a paradigm shift. For users running our tool alongside IntelliJ, Docker, and Chrome tabs, saving 500MB of RAM is a tangible quality-of-life improvement. The installer size reduction also meant we could push updates faster to our remote clients with limited bandwidth.
When NOT to Use Flutter Desktop
Despite the glowing benchmarks, Flutter is not a silver bullet. During our migration, we hit several walls that nearly forced us to roll back.
First, the plugin ecosystem for desktop is still maturing compared to Node.js. In Electron, if you need to access a specific Windows registry key or a weird Linux driver, there is likely an NPM package for it that has been battle-tested for 10 years. In Flutter, we often had to write our own platform channels (C++ for Windows, Swift for macOS) to achieve the same system-level integration.
Second, Text Rendering quirks. While Impeller is great, we noticed subtle differences in font aliasing on Windows compared to native apps. Electron uses the Chromium font rendering engine, which users are very accustomed to because it looks exactly like the web. Flutter draws text itself, and on some lower-resolution monitors, the anti-aliasing can look slightly "thinner" or different than standard OS controls. If your app is text-heavy (like a document editor), test this thoroughly.
Conclusion
If your priority is raw performance, low memory footprint, and smaller distribution size, Flutter is the superior choice in 2025. The trade-off is a steeper learning curve and a smaller package ecosystem for OS-specific tasks. However, if your application relies heavily on existing web libraries or requires pixel-perfect matching with a SaaS web platform, Electron remains the safer, albeit heavier, bet.
Post a Comment