A Comprehensive Guide to Creating a Scalable Folder Structure for Flutter Apps
Tags: flutter, programming, tutorial, mobile
Published: 2023-08-19 16:05:55

Yo wassup flutter devs!!!

Flutter, the UI toolkit from Google, has been gaining immense popularity among developers for its flexibility and efficiency. 

One of the challenges that developers often face when working with Flutter is organizing their project in a scalable and maintainable manner. 

The folder structure plays a pivotal role in this. 

Let's dive deep into how you can structure your Flutter app for scalability.

![Flutter Logo](https://flutter.dev/images/flutter-logo-sharing.png)

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## The Importance of Folder Structure

Selecting the right folder structure for your Flutter application is an essential step. It directly impacts the maintainability, scalability, and ease of collaboration when working with a team.

Given that Flutter does not impose a strict folder structure, developers have the freedom to choose one that best fits their needs.

However, this freedom can also lead to confusion, especially for large projects.

---

## Common Patterns in Flutter Folder Structure

There are two prevalent patterns in the Flutter community:

### Folders By Type/Domain:
This is the most common pattern. Here, files are organized based on their functionality or type.

For instance, all screens would be placed in a folder named 'screens', data models in 'models', and so on. This structure is intuitive and beginner-friendly.

However, it may become cumbersome for larger projects with numerous files.

```
lib/
├── screens/
├── widgets/
├── services/
├── view_models/
├── services/
└── ...
```


### Folders By Feature:
Ideal for larger projects, this pattern organizes files based on features. 

Each feature has its folder, containing screens, widgets, controllers, and services related to that feature.

This approach ensures better organization and easier navigation.

```
lib/
├── feature_1/
│   ├── screens/
│   ├── widgets/
│   ├── models/
│   ├── services/
│   └── view_models/
├── feature_2/
│   ├── screens/
│   ├── widgets/
│   ├── models/
│   ├── services/
│   └── view_models/
└── ...
```

---

## A Deeper Dive into the 'Folder by Feature' Pattern

For those looking to adopt the 'Folder by Feature' pattern, there's a CLI tool that can help set up the structure. The tool generates a structure as follows:

```
feature1/
├── domain/
│   ├── models/
│   │   └── feature1_model.dart
│   ├── repository/
│   │   └── feature1_repository.dart
│   ├── services/
│   │   └── feature1_service.dart
│   └── feature1_domain.dart
├── providers/
│   ├── feature1_provider.dart
│   └── providers.dart
├── screens/
│   ├── feature1_screen.dart
│   └── screens.dart
├── widgets/
│   ├── feature1_widget.dart
│   └── widgets.dart
└── index.dart
```


You can check out the CLI tool [here](https://pub.dev/packages/feature_folder_cli).

---

## Bonus Tip: Code Organization and Modularity

Another effective approach to code organization is extracting common code pieces into packages. This can be achieved in various ways:

- Publishing a package to pub.dev
- Uploading to a remote git repository
- Having them in the same codebase as separate folders

```
lib/
└── packages/
    ├── pkg_1/
    │   ├── lib/
    │   └── pubspec.yaml
```

Each package will have its `pubspec.yaml` file containing dependencies specific to that package.

---

## Conclusion

The choice of folder structure largely depends on the scale and complexity of your Flutter project. For larger projects, having an opinionated pattern is beneficial as it ensures consistency, even if it introduces some boilerplate code. The key is to find a balance that suits your project's needs and enhances your development experience.

Thank you for reading! If you found this guide helpful, please share it with fellow Flutter enthusiasts.

*This blog post is inspired by [Ryan Dsilva's article](https://medium.com/flutter-community/scalable-folder-structure-for-flutter-applications-183746bdc320) on Medium, so thanks to him.*

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