Clean Architecture: A Craftsman's Guide to Software Structure and Design

Uncle Bob’s legendary guide reveals timeless architecture rules that eliminate framework dependencies and enable systems to evolve gracefully—essential for building platforms that outlast technology trends.

Who This Is For

Staff+ engineers designing systems from scratch or refactoring legacy codebases. Platform architects building developer platforms that must adapt to changing technology stacks. Technical leads making architectural decisions that impact team velocity. Senior developers who want to build maintainable, testable systems that outlive frameworks and databases.

Key Takeaways

• The Dependency Rule: source code dependencies must point inward toward higher-level policies; outer layers (frameworks, databases, UI) depend on inner layers (business rules), never the reverse, enabling plugin architecture patterns.
• Treat frameworks as tools, not foundations—business rules should remain isolated from web frameworks, ORMs, and external dependencies to prevent architectural lock-in and enable easy replacement.
• Screaming Architecture: system structure should reveal intent and use cases at first glance; folder names should describe business domains, not technical frameworks, making the application’s purpose immediately obvious.
• Component cohesion principles (REP, CCP, CRP) organize code into components that change together and minimize unnecessary dependencies, reducing coupling and improving reusability.
• Use case boundaries encapsulate application-specific business rules in interactors that orchestrate entity flows while remaining isolated from UI, database, and external concerns for maximum testability.