Project Structure

A project created with flutter create holds your Dart code, package configuration and one native project per platform. This chapter explains what each file and folder does and how to manage dependencies and assets.

The big picture

hello_app/
├── lib/
│   └── main.dart          # App entry point
├── test/
│   └── widget_test.dart   # Default widget test
├── android/               # Android project (Gradle)
├── ios/                   # iOS project (Xcode)
├── web/                   # index.html, icons, manifest
├── windows/               # Windows desktop (CMake)
├── macos/                 # macOS desktop (Xcode)
├── linux/                 # Linux desktop (CMake)
├── pubspec.yaml           # Package configuration
├── pubspec.lock           # Resolved dependency versions
└── analysis_options.yaml  # Static analysis (lint) rules

build/ and .dart_tool/ are generated during builds and stay out of version control; the generated .gitignore already excludes them.

lib: your app code

All Dart code for the app lives under lib. It starts with just main.dart; as the app grows you split it by screens, widgets and data layers. Flutter does not enforce a layout, but this one is common:

lib/
├── main.dart
├── app.dart              # MaterialApp, theme, routing
├── screens/              # One widget per screen
│   ├── home_screen.dart
│   └── detail_screen.dart
├── widgets/              # Widgets shared across screens
├── models/               # Data classes
└── services/             # API clients, storage

Import other files with package paths. If the name in pubspec.yaml is hello_app:

import 'package:flutter/material.dart';
import 'package:hello_app/screens/home_screen.dart';
import 'package:hello_app/models/todo.dart';

Dart convention is snake_case for file names (home_screen.dart) and UpperCamelCase for classes (HomeScreen).

pubspec.yaml: package configuration

pubspec.yaml declares the app name, version, Dart SDK constraint, dependencies and assets.

name: hello_app
description: "A new Flutter project."
publish_to: 'none'
version: 1.0.0+1

environment:
  sdk: ^3.5.0

dependencies:
  flutter:
    sdk: flutter
  cupertino_icons: ^1.0.8
  http: ^1.2.0

dev_dependencies:
  flutter_test:
    sdk: flutter
  flutter_lints: ^5.0.0

flutter:
  uses-material-design: true
  assets:
    - assets/images/
    # Single files can be listed too
    - assets/data/config.json

The version numbers above are only examples; flutter create and flutter pub add fill in current versions. In , the part before is the user-facing version name and the part after it is the build number the stores use.