Modular-Monolith-First: Sizing Architecture to the Problem, Not the Fashion
There's a reflex in our industry, and I had it too: a new business domain shows up, and the hand reaches for "…so that's a new microservice." It feels modern. It feels scalable. It feels like what serious engineers do.
On the ktayl-solution information system — a six-node Kubernetes platform running a simulated insurer's entire IS — I'd built four domains exactly that way: policy, claims, underwriting, identity, each its own repo, CI pipeline, database, promotion track. Then I stopped and asked the question that matters more than any framework choice: is this the right architecture, or just the fashionable one?
This post is the answer I arrived at — modular-monolith-first — and, honestly, the more valuable half: the decision I deliberately didn't make.