The Pendulum of Software Architecture: Wisdom from Monoliths to Microservices and Beyond

The field of Information Technology is one of constant change. Every few years, new architectural approaches emerge, promising to solve all development problems. However, these changes often stem more from developers' frustrations than from an in-depth analysis of the real challenges we face daily.

Over the years, we have seen the pendulum swing from monolithic architectures to microservices and now, it seems, back to modular monoliths. Each of these shifts has come with promises of greater flexibility, scalability, and simplicity in development. But what lessons have we learned?

Monolithic architectures, once the standard, are often viewed today as inflexible and difficult to manage.

As shown in the diagram, in a monolithic architecture, all components are tightly coupled, making it challenging to update or scale individual parts.

On the other hand, the rise of microservices promised the simplicity and scalability of independently deployable small services.

However, as seen in this diagram, microservices also introduced non-trivial complexity. Communication between services, distributed transactions, and data consistency are tough challenges.

Now the focus has shifted to modular monoliths, which attempt to combine the simplicity of monoliths with the modularity of microservices.

In this model, the system is divided into clear modules but maintained within a single monolithic application. This offers some flexibility but may still encounter some of the limitations of monoliths.

Each of these approaches has its strengths and weaknesses. The key issue here is a deep understanding of the business domain and correctly defining service boundaries using Domain-Driven Design (DDD) principles.

DDD focuses on "Bounded Contexts" and "Aggregates" created around domain logic, which help us find the right granularity for our services.

But this is in an ideal world. In real life, business rules often cross the boundaries of individual services.

As this diagram shows, in a real scenario, placing an order depends on checking inventory and charging the customer, crossing service boundaries. Managing such dependencies is challenging in any architecture.

From these experiences, we must draw the main lesson: successful architecture requires solid domain knowledge, analytical thinking, and careful design. We need to delve into the fundamental problems of the business and then select the appropriate technical tools.

The world of software will continue to evolve with new paradigms. But the basic principles—clear concepts, business-oriented service boundaries, reasonable decomposition—will always be the key to success, beyond trends.

Our task is to analyze the current path objectively, get to the essence of the problems, and not be dazzled by superficial solutions. Developing software is a complex endeavor. It requires insight, maturity, and continuous learning. But if we learn the lessons of the past and delve into the essence, we will surely find the path to real success.