Flutter App Architecture

7 mins

7 mins

Sahaj Rana

Published on Apr 4, 2025

Flutter App Architecture Case Study: MVVM in a Real-World Travel Booking App

Flutter Architecture Case Study: MVVM with Compass App
Flutter Architecture Case Study: MVVM with Compass App

This blog presents a practical case study of building a production-quality Flutter application using the MVVM (Model-View-ViewModel) architectural pattern. We will walk through the Compass app—an itinerary and travel booking sample application developed to simulate real-world complexity—and demonstrate how it follows Flutter’s official architecture guidelines.

About the Compass App

The Compass app is designed to reflect the structure and requirements of a modern, scalable Flutter application. It includes:

  • HTTP server integration

  • Development and production build environments

  • Custom themes and brand-specific styling

  • Multiple user-facing screens and routes

  • Comprehensive test coverage

This makes it an ideal reference for developers working on complex projects.

This blog presents a practical case study of building a production-quality Flutter application using the MVVM (Model-View-ViewModel) architectural pattern. We will walk through the Compass app—an itinerary and travel booking sample application developed to simulate real-world complexity—and demonstrate how it follows Flutter’s official architecture guidelines.

About the Compass App

The Compass app is designed to reflect the structure and requirements of a modern, scalable Flutter application. It includes:

  • HTTP server integration

  • Development and production build environments

  • Custom themes and brand-specific styling

  • Multiple user-facing screens and routes

  • Comprehensive test coverage

This makes it an ideal reference for developers working on complex projects.

This blog presents a practical case study of building a production-quality Flutter application using the MVVM (Model-View-ViewModel) architectural pattern. We will walk through the Compass app—an itinerary and travel booking sample application developed to simulate real-world complexity—and demonstrate how it follows Flutter’s official architecture guidelines.

About the Compass App

The Compass app is designed to reflect the structure and requirements of a modern, scalable Flutter application. It includes:

  • HTTP server integration

  • Development and production build environments

  • Custom themes and brand-specific styling

  • Multiple user-facing screens and routes

  • Comprehensive test coverage

This makes it an ideal reference for developers working on complex projects.

This blog presents a practical case study of building a production-quality Flutter application using the MVVM (Model-View-ViewModel) architectural pattern. We will walk through the Compass app—an itinerary and travel booking sample application developed to simulate real-world complexity—and demonstrate how it follows Flutter’s official architecture guidelines.

About the Compass App

The Compass app is designed to reflect the structure and requirements of a modern, scalable Flutter application. It includes:

  • HTTP server integration

  • Development and production build environments

  • Custom themes and brand-specific styling

  • Multiple user-facing screens and routes

  • Comprehensive test coverage

This makes it an ideal reference for developers working on complex projects.

Architecture Pattern: MVVM

Architecture Pattern: MVVM

Architecture Pattern: MVVM

Architecture Pattern: MVVM


The architecture of the Compass app aligns with Flutter's recommended MVVM pattern. This case study specifically focuses on the Home feature, which provides functionalities such as:

  • Displaying the user’s saved trips

  • Navigating to detailed trip pages

  • Logging out

  • Deleting trips

  • Creating a new travel itinerary

MVVM is used here to clearly separate UI logic from business logic, making the app easier to test, scale, and maintain.

What You Will Learn

  1. Layered Architecture:

    • Data layer: Repositories and services that manage data sources.

    • Domain layer: Application-level models shared between layers.

    • UI layer: Feature-specific views and view models using ChangeNotifier for state management.

  2. Command Pattern in UI:
    UI elements are updated in a controlled way using command objects, improving state safety and predictability.

  3. Dependency Injection with Provider:
    Dependencies are managed using the provider package, enabling cleaner and more modular code.

  4. Testing and Structure:

    • The test/ folder mirrors the lib/ directory structure for consistency.

    • The testing/ folder contains mocks and utilities to support unit and widget testing.


The architecture of the Compass app aligns with Flutter's recommended MVVM pattern. This case study specifically focuses on the Home feature, which provides functionalities such as:

  • Displaying the user’s saved trips

  • Navigating to detailed trip pages

  • Logging out

  • Deleting trips

  • Creating a new travel itinerary

MVVM is used here to clearly separate UI logic from business logic, making the app easier to test, scale, and maintain.

What You Will Learn

  1. Layered Architecture:

    • Data layer: Repositories and services that manage data sources.

    • Domain layer: Application-level models shared between layers.

    • UI layer: Feature-specific views and view models using ChangeNotifier for state management.

  2. Command Pattern in UI:
    UI elements are updated in a controlled way using command objects, improving state safety and predictability.

  3. Dependency Injection with Provider:
    Dependencies are managed using the provider package, enabling cleaner and more modular code.

  4. Testing and Structure:

    • The test/ folder mirrors the lib/ directory structure for consistency.

    • The testing/ folder contains mocks and utilities to support unit and widget testing.


The architecture of the Compass app aligns with Flutter's recommended MVVM pattern. This case study specifically focuses on the Home feature, which provides functionalities such as:

  • Displaying the user’s saved trips

  • Navigating to detailed trip pages

  • Logging out

  • Deleting trips

  • Creating a new travel itinerary

MVVM is used here to clearly separate UI logic from business logic, making the app easier to test, scale, and maintain.

What You Will Learn

  1. Layered Architecture:

    • Data layer: Repositories and services that manage data sources.

    • Domain layer: Application-level models shared between layers.

    • UI layer: Feature-specific views and view models using ChangeNotifier for state management.

  2. Command Pattern in UI:
    UI elements are updated in a controlled way using command objects, improving state safety and predictability.

  3. Dependency Injection with Provider:
    Dependencies are managed using the provider package, enabling cleaner and more modular code.

  4. Testing and Structure:

    • The test/ folder mirrors the lib/ directory structure for consistency.

    • The testing/ folder contains mocks and utilities to support unit and widget testing.


The architecture of the Compass app aligns with Flutter's recommended MVVM pattern. This case study specifically focuses on the Home feature, which provides functionalities such as:

  • Displaying the user’s saved trips

  • Navigating to detailed trip pages

  • Logging out

  • Deleting trips

  • Creating a new travel itinerary

MVVM is used here to clearly separate UI logic from business logic, making the app easier to test, scale, and maintain.

What You Will Learn

  1. Layered Architecture:

    • Data layer: Repositories and services that manage data sources.

    • Domain layer: Application-level models shared between layers.

    • UI layer: Feature-specific views and view models using ChangeNotifier for state management.

  2. Command Pattern in UI:
    UI elements are updated in a controlled way using command objects, improving state safety and predictability.

  3. Dependency Injection with Provider:
    Dependencies are managed using the provider package, enabling cleaner and more modular code.

  4. Testing and Structure:

    • The test/ folder mirrors the lib/ directory structure for consistency.

    • The testing/ folder contains mocks and utilities to support unit and widget testing.

Project Folder Structure

Project Folder Structure

Project Folder Structure

Project Folder Structure

The Compass application follows a clean and hybrid folder structure:

Test files are placed in:

This setup improves scalability and developer onboarding while reducing code conflicts.

The Compass application follows a clean and hybrid folder structure:

Test files are placed in:

This setup improves scalability and developer onboarding while reducing code conflicts.

The Compass application follows a clean and hybrid folder structure:

Test files are placed in:

This setup improves scalability and developer onboarding while reducing code conflicts.

The Compass application follows a clean and hybrid folder structure:

Test files are placed in:

This setup improves scalability and developer onboarding while reducing code conflicts.

Feature-Based vs Type-Based Organization

Feature-Based vs Type-Based Organization

Feature-Based vs Type-Based Organization

Feature-Based vs Type-Based Organization

The Compass app combines both organizational styles:

  • Feature-based: Used in the UI layer, where each feature is self-contained.

  • Type-based: Used in the data layer, where services and repositories are shared across multiple features.

This balance ensures flexibility and modularity, especially in larger codebases.

The Compass app combines both organizational styles:

  • Feature-based: Used in the UI layer, where each feature is self-contained.

  • Type-based: Used in the data layer, where services and repositories are shared across multiple features.

This balance ensures flexibility and modularity, especially in larger codebases.

The Compass app combines both organizational styles:

  • Feature-based: Used in the UI layer, where each feature is self-contained.

  • Type-based: Used in the data layer, where services and repositories are shared across multiple features.

This balance ensures flexibility and modularity, especially in larger codebases.

The Compass app combines both organizational styles:

  • Feature-based: Used in the UI layer, where each feature is self-contained.

  • Type-based: Used in the data layer, where services and repositories are shared across multiple features.

This balance ensures flexibility and modularity, especially in larger codebases.

Other Architectural Alternatives

Other Architectural Alternatives

Other Architectural Alternatives

Other Architectural Alternatives

While MVVM with ChangeNotifier is used here, the same principles could be applied using different tools or patterns, such as:

  • flutter_bloc

  • Riverpod

  • Streams for data communication

The application’s logic and architecture remain intact regardless of the state management solution chosen.

While MVVM with ChangeNotifier is used here, the same principles could be applied using different tools or patterns, such as:

  • flutter_bloc

  • Riverpod

  • Streams for data communication

The application’s logic and architecture remain intact regardless of the state management solution chosen.

While MVVM with ChangeNotifier is used here, the same principles could be applied using different tools or patterns, such as:

  • flutter_bloc

  • Riverpod

  • Streams for data communication

The application’s logic and architecture remain intact regardless of the state management solution chosen.

While MVVM with ChangeNotifier is used here, the same principles could be applied using different tools or patterns, such as:

  • flutter_bloc

  • Riverpod

  • Streams for data communication

The application’s logic and architecture remain intact regardless of the state management solution chosen.

Conclusion

Conclusion

Conclusion

Conclusion

This case study demonstrates how to implement Flutter’s architectural best practices in a realistic application. While the Compass app uses MVVM and Provider, the broader principles—separation of concerns, dependency management, testability, and code structure—are universal.

Whether you're starting a new project or refactoring an existing one, applying these patterns will help you build scalable and maintainable Flutter applications.

For full implementation details, you can explore the Compass app on GitHub.

This case study demonstrates how to implement Flutter’s architectural best practices in a realistic application. While the Compass app uses MVVM and Provider, the broader principles—separation of concerns, dependency management, testability, and code structure—are universal.

Whether you're starting a new project or refactoring an existing one, applying these patterns will help you build scalable and maintainable Flutter applications.

For full implementation details, you can explore the Compass app on GitHub.

This case study demonstrates how to implement Flutter’s architectural best practices in a realistic application. While the Compass app uses MVVM and Provider, the broader principles—separation of concerns, dependency management, testability, and code structure—are universal.

Whether you're starting a new project or refactoring an existing one, applying these patterns will help you build scalable and maintainable Flutter applications.

For full implementation details, you can explore the Compass app on GitHub.

This case study demonstrates how to implement Flutter’s architectural best practices in a realistic application. While the Compass app uses MVVM and Provider, the broader principles—separation of concerns, dependency management, testability, and code structure—are universal.

Whether you're starting a new project or refactoring an existing one, applying these patterns will help you build scalable and maintainable Flutter applications.

For full implementation details, you can explore the Compass app on GitHub.

Frequently Asked Questions (FAQs)

Frequently Asked Questions (FAQs)

Frequently Asked Questions (FAQs)

Frequently Asked Questions (FAQs)

1. What is the MVVM architecture in Flutter?

MVVM (Model-View-ViewModel) is a design pattern that separates the user interface (View) from business logic (ViewModel) and data models (Model). It enhances code maintainability, testability, and scalability in Flutter apps.

2. Why did the Compass app choose MVVM over other patterns like BLoC or Riverpod?

MVVM is clean, simple, and integrates well with ChangeNotifier and Provider, which are both easy to use and understand for most Flutter teams. It suits projects that need clear separation of concerns without too much boilerplate.

3. How is state managed in the Compass app?

State is managed using ChangeNotifier and Listenable. ViewModels notify the UI when data changes, ensuring the UI stays reactive and updated.

4. What are repositories and services in the Compass architecture?

  • Repositories act as the bridge between the app and data sources (APIs, local storage).

  • Services handle API requests or complex business logic.
    Both are part of the data layer, separate from UI logic.

5. What does the folder structure look like in a large Flutter app?

The Compass app follows a hybrid approach:

  • UI Layer: Organized by features

  • Data Layer: Organized by type (repositories, services, models)

  • This improves modularity and supports scalable team collaboration.

6. How is dependency injection handled in the Compass app?

The app uses the provider package for injecting services and view models into the widget tree, enabling better modularity and testability.

7. How are tests structured in the Compass app?

  • Unit tests and widget tests are stored in the test/ folder, which mirrors the lib/ structure.

  • The testing/ folder contains reusable mocks and fakes for more complex testing setups.

8. Can I replace ChangeNotifier with other state management tools like Riverpod or BLoC?

Yes, the architecture is flexible. You can swap ChangeNotifier with flutter_bloc, Riverpod, or other state management solutions while keeping the MVVM separation intact.

9. Does this architecture support scalability for large teams?

Yes, it’s designed for collaboration. Clear separation of features, test coverage, and code reuse make it easy for multiple developers to contribute without stepping on each other's work.

10. Where can I find the full Compass app source code?

The complete source code, including examples, folder structure, and test setups, is available on GitHub. (Insert link to the GitHub repo if applicable.)

1. What is the MVVM architecture in Flutter?

MVVM (Model-View-ViewModel) is a design pattern that separates the user interface (View) from business logic (ViewModel) and data models (Model). It enhances code maintainability, testability, and scalability in Flutter apps.

2. Why did the Compass app choose MVVM over other patterns like BLoC or Riverpod?

MVVM is clean, simple, and integrates well with ChangeNotifier and Provider, which are both easy to use and understand for most Flutter teams. It suits projects that need clear separation of concerns without too much boilerplate.

3. How is state managed in the Compass app?

State is managed using ChangeNotifier and Listenable. ViewModels notify the UI when data changes, ensuring the UI stays reactive and updated.

4. What are repositories and services in the Compass architecture?

  • Repositories act as the bridge between the app and data sources (APIs, local storage).

  • Services handle API requests or complex business logic.
    Both are part of the data layer, separate from UI logic.

5. What does the folder structure look like in a large Flutter app?

The Compass app follows a hybrid approach:

  • UI Layer: Organized by features

  • Data Layer: Organized by type (repositories, services, models)

  • This improves modularity and supports scalable team collaboration.

6. How is dependency injection handled in the Compass app?

The app uses the provider package for injecting services and view models into the widget tree, enabling better modularity and testability.

7. How are tests structured in the Compass app?

  • Unit tests and widget tests are stored in the test/ folder, which mirrors the lib/ structure.

  • The testing/ folder contains reusable mocks and fakes for more complex testing setups.

8. Can I replace ChangeNotifier with other state management tools like Riverpod or BLoC?

Yes, the architecture is flexible. You can swap ChangeNotifier with flutter_bloc, Riverpod, or other state management solutions while keeping the MVVM separation intact.

9. Does this architecture support scalability for large teams?

Yes, it’s designed for collaboration. Clear separation of features, test coverage, and code reuse make it easy for multiple developers to contribute without stepping on each other's work.

10. Where can I find the full Compass app source code?

The complete source code, including examples, folder structure, and test setups, is available on GitHub. (Insert link to the GitHub repo if applicable.)

1. What is the MVVM architecture in Flutter?

MVVM (Model-View-ViewModel) is a design pattern that separates the user interface (View) from business logic (ViewModel) and data models (Model). It enhances code maintainability, testability, and scalability in Flutter apps.

2. Why did the Compass app choose MVVM over other patterns like BLoC or Riverpod?

MVVM is clean, simple, and integrates well with ChangeNotifier and Provider, which are both easy to use and understand for most Flutter teams. It suits projects that need clear separation of concerns without too much boilerplate.

3. How is state managed in the Compass app?

State is managed using ChangeNotifier and Listenable. ViewModels notify the UI when data changes, ensuring the UI stays reactive and updated.

4. What are repositories and services in the Compass architecture?

  • Repositories act as the bridge between the app and data sources (APIs, local storage).

  • Services handle API requests or complex business logic.
    Both are part of the data layer, separate from UI logic.

5. What does the folder structure look like in a large Flutter app?

The Compass app follows a hybrid approach:

  • UI Layer: Organized by features

  • Data Layer: Organized by type (repositories, services, models)

  • This improves modularity and supports scalable team collaboration.

6. How is dependency injection handled in the Compass app?

The app uses the provider package for injecting services and view models into the widget tree, enabling better modularity and testability.

7. How are tests structured in the Compass app?

  • Unit tests and widget tests are stored in the test/ folder, which mirrors the lib/ structure.

  • The testing/ folder contains reusable mocks and fakes for more complex testing setups.

8. Can I replace ChangeNotifier with other state management tools like Riverpod or BLoC?

Yes, the architecture is flexible. You can swap ChangeNotifier with flutter_bloc, Riverpod, or other state management solutions while keeping the MVVM separation intact.

9. Does this architecture support scalability for large teams?

Yes, it’s designed for collaboration. Clear separation of features, test coverage, and code reuse make it easy for multiple developers to contribute without stepping on each other's work.

10. Where can I find the full Compass app source code?

The complete source code, including examples, folder structure, and test setups, is available on GitHub. (Insert link to the GitHub repo if applicable.)

1. What is the MVVM architecture in Flutter?

MVVM (Model-View-ViewModel) is a design pattern that separates the user interface (View) from business logic (ViewModel) and data models (Model). It enhances code maintainability, testability, and scalability in Flutter apps.

2. Why did the Compass app choose MVVM over other patterns like BLoC or Riverpod?

MVVM is clean, simple, and integrates well with ChangeNotifier and Provider, which are both easy to use and understand for most Flutter teams. It suits projects that need clear separation of concerns without too much boilerplate.

3. How is state managed in the Compass app?

State is managed using ChangeNotifier and Listenable. ViewModels notify the UI when data changes, ensuring the UI stays reactive and updated.

4. What are repositories and services in the Compass architecture?

  • Repositories act as the bridge between the app and data sources (APIs, local storage).

  • Services handle API requests or complex business logic.
    Both are part of the data layer, separate from UI logic.

5. What does the folder structure look like in a large Flutter app?

The Compass app follows a hybrid approach:

  • UI Layer: Organized by features

  • Data Layer: Organized by type (repositories, services, models)

  • This improves modularity and supports scalable team collaboration.

6. How is dependency injection handled in the Compass app?

The app uses the provider package for injecting services and view models into the widget tree, enabling better modularity and testability.

7. How are tests structured in the Compass app?

  • Unit tests and widget tests are stored in the test/ folder, which mirrors the lib/ structure.

  • The testing/ folder contains reusable mocks and fakes for more complex testing setups.

8. Can I replace ChangeNotifier with other state management tools like Riverpod or BLoC?

Yes, the architecture is flexible. You can swap ChangeNotifier with flutter_bloc, Riverpod, or other state management solutions while keeping the MVVM separation intact.

9. Does this architecture support scalability for large teams?

Yes, it’s designed for collaboration. Clear separation of features, test coverage, and code reuse make it easy for multiple developers to contribute without stepping on each other's work.

10. Where can I find the full Compass app source code?

The complete source code, including examples, folder structure, and test setups, is available on GitHub. (Insert link to the GitHub repo if applicable.)

Top Blogs

Sahaj Rana

Sahaj Rana

Flutter App Architecture Case Study: MVVM in a Real-World Travel Booking App

Flutter App Architecture Case Study: MVVM in a Real-World Travel Booking App

Flutter Architecture Case Study: MVVM with Compass App
Flutter Architecture Case Study: MVVM with Compass App

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