Boundaries first. Components second.
Useful architecture explains where data begins, who may change it and what happens when a dependency fails.
System boundaries
User interface, server logic, storage, external services and administration receive explicit ownership and contracts.
Data and roles
The model records identity, tenant or business unit, permissions, change history and validation rules.
Failure is a state
Empty, loading, rejection, timeout and partial success are designed as visible states rather than an afterthought.
Operational handoff
Backups, migrations, monitoring, logs, rollback and operating notes enter the plan before production.