Designing the Domain Layer in Hexagonal Architecture

Tangled business logic and database dependencies make software difficult to test, maintain, and scale. Hexagonal architecture solves this by isolating your core domain logic from external frameworks, databases, and user interfaces. This written course guides you through the process of designing a clean, independent domain layer. You will learn how to model real-world business rules using pure code, ensuring your application remains adaptable to change and easy to test. What you'll learn: Understand the core principles of hexagonal architecture and the role of the domain layer; Model business concepts using entities, value objects, and aggregates; Enforce immutability and type safety to prevent invalid domain states; Design clean repository interfaces to decouple your logic from database implementations; Write isolated unit tests for your domain logic without relying on external infrastructure. You will start with the fundamental terminology and concepts of clean architecture before moving into practical code structures. Through step-by-step written explanations and clear code snippets, you will see how to build a robust domain model from scratch. This course is designed for software developers and aspiring architects who want to improve their system design skills, and no prior experience with hexagonal architecture is required. Start reading today to build cleaner, more maintainable software systems.