A Practical Guide to Service Boundaries
Notes on when to split services, when to stay modular, and how to avoid accidental distributed complexity.
Service boundaries are not only technical boundaries. They create ownership, deployment, testing, monitoring, and communication boundaries too. A service split can reduce complexity when the domain is stable and ownership is clear. It can also make simple changes painfully distributed.
Before splitting a service, look for the pressure behind the decision. Independent scaling, independent deployment, data ownership, and team boundaries are stronger reasons than folder size alone.
Questions worth asking
- Does this boundary match a business capability?
- Can the service own its data without constant cross-service joins?
- Will the new boundary reduce coordination or increase it?
- Can failures be isolated clearly?
Modularity inside one deployable unit is often the better first move. Split later when the operational benefits are real.