The hard part of enterprise software is not the first release — it is the fiftieth change request two years later. Architecture is what determines whether that change takes an hour or a week.
Boundaries first
We organize around clear domain boundaries, keep business logic out of controllers, and treat the database as an implementation detail behind well-defined interfaces. This keeps the system easy to test and easy to evolve.
Observability is not optional
Structured logging, metrics, and tracing go in from the start. When something breaks at 2am, the difference between minutes and hours of downtime is whether you can see what is happening.