**Domain-Driven Hexagon** is a comprehensive guide to designing robust, scalable, and maintainable software applications by combining architectural patterns like Domain-Driven Design (DDD), Hexagonal Architecture, Clean Architecture, and SOLID principles. It provides best practices, tools, and guidelines for structuring applications into modular, loosely coupled components. The project emphasizes separation of concerns, with distinct layers for domain logic, application services, and infrastructure. It includes code examples in Node.js, TypeScript, NestJS, and Slonik, but the principles are framework-agnostic, applicable to any language or stack. Key features include modular design, command-query separation, domain events, value objects, and behavioral testing. The architecture promotes testability, security, and scalability, making it suitable for complex systems while offering flexibility for simpler applications.