In the world of software development, staying ahead of the curve is essential. As technology evolves at a rapid pace, developers are constantly seeking efficient and maintainable approaches to building robust applications. One such approach that has gained significant traction is Clean Architecture.

In this article Morrow's senior developer, and winner of our 2023 AI Hackathon, Ivan, delves into the origins, core concepts, popularity, benefits, and drawbacks of Clean Architecture, making a case for its effectiveness in building sustainable software.

What is Clean Architecture

Clean Architecture is a software design philosophy introduced by Robert C. Martin, also known as Uncle Bob, in his book "Clean Architecture: A Craftsman's Guide to Software Structure and Design." It is an evolution of previous architectural patterns, such as Domain-Driven Design (DDD) and Hexagonal Architecture. At its core, Clean Architecture promotes the separation of concerns by dividing the application into layers and enforcing dependencies to flow inward, keeping the inner layers independent of the outer layers.

With its emphasis on separation of concerns and flexibility, Clean Architecture offers a practical solution to the challenges developers face in managing complex software systems.

Why Clean Architecture is Popular

The popularity of Clean Architecture stems from its ability to address some of the most pressing challenges developers face. One key advantage is its focus on maintainability. By decoupling the application's core business logic from external frameworks, databases, and user interfaces, Clean Architecture enables easy modification and testing of individual components without impacting the entire system. This makes it an ideal choice for large-scale projects or applications that require frequent updates.

Using clean architecture gives you major benefits that enable you to move quickly.
Testability

Clean Architecture encourages writing isolated unit tests for each component, facilitating comprehensive test coverage and enabling developers to catch bugs early in the development process. Testing becomes more manageable as dependencies are abstracted away, allowing for the use of mock objects or test doubles.

Modularity and Scalability

The architectural layers of Clean Architecture enable developers to achieve modular design. This modular approach simplifies codebase maintenance and facilitates the addition or removal of features without causing ripple effects throughout the application.

Independence from Frameworks

Clean Architecture prioritises the separation of concerns between the business logic and the external frameworks or libraries. This independence allows developers to replace or upgrade frameworks without affecting the application's core functionality, reducing vendor lock-in and enabling future-proofing.

At Morrow, we do this with our React Native applications by using "dumb" components that only represent the current state of the application, and all business logic is abstracted away in separate application classes powered by Mobx.

Downsides of Clean Architecture

While Clean Architecture brings numerous benefits to modern front-end web development, it's essential to consider its implementation's potential downsides and challenges. In the next section, I will list some of the concerns and counterarguments to those concerns.

First one on the list, and from my personal experience, the one that is most talked about:

Over-Engineering for Small Projects

Clean Architecture is best used in complex, large-scale projects with multiple modules and teams. However, the additional layers and abstractions may introduce unnecessary complexity and overhead for smaller projects or prototypes. A simpler architectural approach or framework may be more appropriate in such cases.


While Clean Architecture may appear to be over-engineering for small projects, it provides significant benefits even in such scenarios. By adopting Clean Architecture principles, small projects gain scalability and future-proofing capabilities. Clean Architecture enables modular design, separation of concerns, and clear code organisation, making it easier to add new features, modify existing ones, and maintain the codebase over time. Although small projects may not initially require the full complexity of Clean Architecture, the investment in its principles ensures a solid foundation for growth and avoids technical debt accumulation. Embracing Clean Architecture in small projects sets them up for long-term success and reduces the need for significant rework in the future.

Steeper Learning Curve for New Team Members

Though Clean Architecture may have a learning curve for new team members, the benefits of enhanced collaboration and long-term efficiency outweigh the initial investment. Shared knowledge promotes effective teamwork, reduces conflicts, and enables independent work. Providing proper documentation, onboarding, and mentoring can help mitigate this challenge.


Though Clean Architecture may have a learning curve for new team members, the benefits of enhanced collaboration and long-term efficiency outweigh the initial investment. Shared knowledge promotes effective teamwork, reduces conflicts, and enables independent work. Providing proper documentation, onboarding, and mentoring can help mitigate this challenge.

Development Time and Effort


Implementing Clean Architecture may require more development time and effort than traditional approaches. The emphasis on separation of concerns and modular design often entails writing additional code.


While Clean Architecture requires additional development time and effort compared to traditional approaches, the long-term benefits make it worthwhile. By reducing technical debt, improving debugging, enabling better testability, and providing future-proofing capabilities, Clean Architecture ultimately leads to more efficient development processes and reduced maintenance costs.

Performance Impact


Clean Architecture promotes loose coupling between layers, often achieved through interfaces and dependency injection. However, this indirection can introduce a small performance impact due to the additional method calls and object instantiations required.


This is rarely the case. The slight performance trade-off is outweighed by the advantages of maintainability, testability, and flexibility that Clean Architecture offers. The modest performance impact is a worthwhile trade-off for the long-term benefits of a robust and scalable codebase.

Strict Adherence to rules hinders flexibility


Strict adherence to architectural principles may sometimes hinder flexibility and adaptability.


While strict adherence to Clean Architecture principles may seem rigid and potentially hinder flexibility, it is crucial to balance principles and pragmatism. Clean Architecture provides a solid foundation for building maintainable and scalable applications. However, it doesn't mean that every aspect of the architecture must be strictly followed in every situation. If you need to break the rules, break them! Just make sure you have good reasons for doing so and document your reasons so other engineers on the team know why.

Clean Architecture at Morrow

Here at Morrow, we are big fans of Clean Architecture both on the front end and on the back end; we found that it scales well. We have built internal libraries, tools, and workflow procedures based on Clean architecture. This enables us to move quickly and deliver new features fast, and most importantly, it allows us to maintain applications that have been in production for years (legacy code/software is one of the worst things you have to deal with in software development.)

Clean Architecture has emerged as a powerful paradigm for building sustainable and maintainable software systems. By emphasising the separation of concerns, modularity, and testability, it enables developers to create robust applications adaptable to evolving requirements. While it may not be a one-size-fits-all solution, understanding the core concepts and leveraging Clean Architecture's benefits can significantly enhance software projects' quality and longevity.

As the software industry continues to evolve, embracing such architectural patterns becomes increasingly important to ensure the success of complex software systems.

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