Clean Architecture in Flutter: Folder Structure Every Developer Should Follow

Clean Architecture separates your code into independent layers. This ensures that your UI logic doesn't get tangled with your business logic or data sources.

The Three Layers

1. **Presentation**: Widgets, State Management (Bloc/Riverpod). 2. **Domain**: Entities, Usecases, Repository Interfaces (Pure Dart, no Flutter dependencies). 3. **Data**: API calls, Local Database, Repository Implementation.

lib/
├── core/               # Shared utils, errors, constants
├── features/
│   ├── authentication/
│   │   ├── data/
│   │   │   ├── datasources/
│   │   │   ├── models/
│   │   │   └── repositories/
│   │   ├── domain/
│   │   │   ├── entities/
│   │   │   ├── repositories/
│   │   │   └── usecases/
│   │   └── presentation/
│   │       ├── bloc/
│   │       ├── pages/
│   │       └── widgets/
└── main.dart

By following this structure, you can swap out your database (e.g., from Firebase to SQL) by only changing the Data layer, without breaking your UI.