When Microservices Are Overkill (Most of the Time)

Microservices solve a real problem, but it's worth being precise about which problem, because most early and mid-stage products don't actually have it yet, and adopting the architecture anyway adds real cost without the benefit it's meant to provide.

The problem microservices actually solve

Independent scaling of different parts of a system under real, differentiated load. Independent deployment for genuinely large teams working on separate parts of a product, where a single deployable unit would create bottlenecks between teams. Fault isolation, so one part of a system failing doesn't take down everything else. These are real, valuable properties, for a system and a team large enough to need them.

What it costs to adopt early anyway

Network calls between services that used to be simple function calls, with all the new failure modes that implies, latency, partial failures, retries. Operational complexity, more moving pieces to deploy, monitor, and debug, at exactly the stage when a small team's time is most scarce. Harder local development and debugging, since reproducing a bug now might mean coordinating several services instead of stepping through one codebase.

Why a single well-organized codebase usually wins early

A well-structured monolith, with clear internal boundaries between modules, can be broken apart later into services if and when the business actually needs to, and by then there's real usage data to inform where those boundaries should be drawn. Guessing at service boundaries before there's real usage data usually means drawing them in the wrong place, and paying to re-draw them later anyway, on top of the complexity already taken on early for no benefit.

When I would actually reach for it

When there's a genuinely large team that needs to deploy independently without stepping on each other, or a specific part of the system with load characteristics wildly different from the rest of the product. Short of those conditions, the operational cost of microservices is usually paid well before the benefit ever shows up.