How to Keep Microservices Loosely Coupled Without Over-Engineering Them

A software engineer argues that the real goal of loose coupling is not eliminating dependencies but ensuring that services only change together when it makes sense. Stable contracts between services — such as defined data types and versioned API payloads — prevent consumers from depending on a producer's internal implementation details. Async messaging via events can decouple service availability, though it introduces trade-offs like the need for idempotency and more complex debugging. Shared databases are identified as the most common source of hidden coupling, preventing independent deployment, scaling, and ownership. The author cautions against over-engineering, noting that a well-structured monolith or a simple function call is often preferable to unnecessary abstractions and message brokers.