Clean Architecture & DDD

Architectural patterns and tactical design techniques for building systems where business logic is isolated, testable, and independent of frameworks, databases, and delivery mechanisms. Rooted in the work of Robert C. Martin, Alistair Cockburn, and Eric Evans.

When to Use

• The domain has meaningful business rules that deserve explicit modeling
• The system must survive framework upgrades, database migrations, or delivery mechanism changes
• Multiple entry points (API, CLI, message consumer, scheduled jobs) share the same business logic
• Long-lived product where maintenance cost outweighs initial development speed
• Team size or turnover demands clear boundaries and enforceable conventions
• Testability is a priority — business rules must be verifiable without infrastructure

When NOT to Use

Not every system benefits from this level of architectural rigor. Avoid over-engineering when: