Clean Architecture

Organizes code into concentric layers where dependencies point inward. Business rules stay independent of frameworks, databases, and external systems.

When to Use

• Backend projects >500 LOC with business logic
• Need to swap databases, frameworks, or external services
• Want business logic testable without spinning up infrastructure
• Building multi-layered services

Don't use for:

• Simple CRUD APIs without real business rules
• Scripts and utilities
• Prototypes