Understand the domain before choosing architecture
Complexity often comes from mixed responsibilities. Clarifying concepts, data ownership, and business constraints matters more than deciding how many services to deploy. Keeping account, project, and permission rules inside explicit domain modules helps contain change.
Complexity inside. Clarity on the outside.
A modular monolith is a practical starting point
A single deployment unit does not imply a lack of boundaries. Modules collaborate through explicit interfaces, without accessing each other’s internal data. Clear dependency direction and boundary tests leave room to evolve while keeping operations manageable.
Let real needs drive separation
Consider separation when a module needs independent scaling, releases, or team ownership. Account for network failures, consistency, observability, and rollback costs first. Good architecture makes change easier to understand and verify.