What is Flutter?
Flutter is Google's open-source UI toolkit for building natively compiled applications for mobile, web, desktop, and embedded devices from a single codebase. Released in 2018 and now at version 3.x, Flutter uses the Dart programming language and includes its own rendering engine (Skia/Impeller), which means it doesn't rely on platform-native UI components.
This architectural decision is what makes Flutter unique — and controversial. Instead of mapping to native widgets, Flutter draws every pixel itself using its own rendering engine. The result is pixel-perfect consistency across platforms and exceptional performance, but it also means Flutter apps look the same on iOS and Android rather than adopting each platform's native visual language.
As of 2025, Flutter powers apps used by hundreds of millions of users globally, including Google Pay, Alibaba's Xianyu, BMW's My BMW app, and eBay Motors.
Flutter's Architecture
Understanding Flutter's architecture helps explain why it performs so well. The framework is structured in three layers:
- Framework layer (Dart): The top layer where developers write code. It includes Material and Cupertino widget libraries, animation, painting, and gesture detection.
- Engine layer (C/C++): The Flutter engine handles rendering via Skia (or the newer Impeller renderer), text layout, file and network I/O, and platform channels for communicating with native code.
- Embedder layer: Platform-specific code that integrates the Flutter engine with the host operating system — iOS, Android, Windows, macOS, Linux, or web.
The key insight is that Flutter compiles Dart code to native ARM machine code, not JavaScript or bytecode. This is why Flutter apps achieve 60fps (and 120fps on supported devices) consistently, even for complex animations.
Key Advantages of Flutter for Mobile Development
1. Single Codebase, Multiple Platforms
A single Flutter codebase deploys to iOS, Android, web, and desktop. For most businesses, this means launching on both major mobile platforms simultaneously without doubling development costs. Arnnima Solution's Flutter projects typically deliver 40–60% cost savings compared to building separate native apps.
2. Hot Reload and Hot Restart
Flutter's hot reload feature lets developers see code changes reflected in the running app in under a second, without losing application state. This dramatically accelerates the development and iteration cycle, particularly during UI development and debugging.
3. Rich Widget Library
Flutter ships with an extensive library of pre-built widgets that implement Material Design and Cupertino (iOS-style) design patterns. Custom widgets are composable and reusable, making it straightforward to build complex, consistent UIs.
4. Excellent Performance
Because Flutter compiles to native ARM code and renders using its own engine, it consistently achieves 60fps performance. The Impeller renderer (default in Flutter 3.10+) further improves rendering predictability and eliminates shader compilation jank.
5. Strong Ecosystem and Community
pub.dev, Flutter's package repository, hosts over 35,000 packages covering everything from state management (Riverpod, BLoC, Provider) to Firebase integration, payment gateways, maps, and AI/ML model inference.
Flutter vs React Native: A Quick Comparison
- Language: Flutter uses Dart; React Native uses JavaScript/TypeScript
- Rendering: Flutter renders its own widgets; React Native uses native platform components
- Performance: Flutter generally edges out React Native for animation-heavy UIs
- Ecosystem: React Native has a larger existing JavaScript ecosystem; Flutter's Dart ecosystem is growing rapidly
- Learning curve: Dart is easy to learn for developers with Java/C# background; React Native is easier for JavaScript developers
When to Use Flutter
Flutter is an excellent choice when:
- You need to launch on both iOS and Android simultaneously
- Your app requires smooth, complex animations or custom UI components
- You want a consistent visual experience across platforms
- You're building a consumer-facing app where UI quality matters
- You want to extend to web or desktop in the future from the same codebase
- Your team is open to learning Dart (which most developers pick up quickly)
When Flutter May Not Be the Best Choice
- Your app requires deep integration with platform-specific features that don't yet have Flutter plugins
- Your team has deep React/JavaScript expertise and React Native is a better fit
- You're building a game that requires a dedicated game engine like Unity
- Your app needs to match the exact native platform UI conventions (e.g., a system settings app)
Getting Started with Flutter Development
The Flutter development workflow involves setting up the Flutter SDK, choosing an IDE (VS Code or Android Studio are both excellent), and using the flutter create command to scaffold a new project. The framework's documentation is among the best in the mobile development ecosystem, and Google's Flutter team is highly active in the community.
For businesses looking to build a Flutter app without building an in-house team, Arnnima Solution offers end-to-end Flutter development services — from product design and architecture through development, testing, and App Store submission. Our Thane-based team has delivered Flutter apps for clients across India, the UK, the US, and the Middle East.