The structure chosen at the start of a system shapes development speed, operating costs, and the ability to scale for years to come. This decision is important for businesses of all sizes, especially SMEs. Limited budgets and smaller development teams leave little margin for error. A traditional monolith architecture offers simplicity and fast early development, but it can become difficult to evolve as the codebase grows. Microservices promise independent scaling and team autonomy, yet they introduce distributed systems complexity, additional tooling, and operational overhead. The modular monolith, which lies between these two extremes, maintains a single deployable system while enforcing clear boundaries between modules. This approach delivers a practical balance of maintainability and operational simplicity. CIOs and IT leaders in SMEs must solve the difficult task of choosing an architecture that aligns with team size, growth plans, and operational maturity. …