What Is Flutter
Flutter is a free, open-source toolkit made by Google. You write code once and it runs on Android, iOS, web, and desktop — all from a single codebase. The language you write that code in is called Dart.
The Problem Flutter Solves
Before Flutter, developers had to build two separate apps — one for Android (using Java or Kotlin) and one for iOS (using Swift or Objective-C). That meant twice the work, twice the bugs, and twice the cost.
Flutter fixes this by letting you write one app that works everywhere.
A Simple Analogy
Think of Flutter like a universal remote control. One remote controls the TV, DVD player, and sound system. One Flutter codebase controls Android, iOS, and web apps.
┌─────────────────────────────────────────────┐
│ YOUR DART CODE │
│ (written once, runs anywhere) │
└────────────────┬────────────────────────────┘
│
┌──────────┼──────────┐
▼ ▼ ▼
[Android] [iOS] [Web]
What Is Dart
Dart is the programming language Flutter uses. Google created Dart in 2011. It looks similar to JavaScript and Java, so many developers pick it up quickly.
Dart compiles to native machine code on mobile devices. This makes Flutter apps fast — they feel as smooth as apps built natively for each platform.
Flutter vs React Native vs Native Development
| Feature | Flutter | React Native | Native (Android/iOS) |
|---|---|---|---|
| Language | Dart | JavaScript | Kotlin / Swift |
| One codebase | Yes | Yes | No |
| Performance | Very fast | Fast | Fastest |
| UI Components | Custom (Widgets) | Platform native | Platform native |
| Learning curve | Moderate | Moderate | High |
How Flutter Draws the Screen
Most cross-platform tools rely on the phone's built-in UI components. Flutter takes a different approach — it draws every pixel on the screen itself using a graphics engine called Skia (now Impeller on newer versions).
Traditional App: Your Code → Platform UI Components → Screen Flutter App: Your Code → Flutter Engine (draws directly) → Screen
This gives Flutter full control over how everything looks and feels, regardless of the device.
Key Features of Flutter
- Hot Reload — See changes in your app instantly without restarting it.
- Widget-based UI — Everything on screen is a widget: buttons, text, images, layouts.
- Rich package library — Thousands of ready-made packages at pub.dev.
- Strong community — Backed by Google with active global support.
Who Uses Flutter
Companies like Google, BMW, Alibaba, eBay, and thousands of startups use Flutter to build their mobile apps. The Google Pay app runs on Flutter.