Domain-Driven Design (DDD) is about building software that reflects the real-world domain by collaborating closely with domain experts, using a ubiquitous language and dividing the system into well-defined bounded contexts.

It is especially powerful in complex systems where business logic is substantial - DDD helps developers organize, encapsulate and express domain logic in a structured, scalable way.

With DDD, teams gain a deeper understanding of business needs, avoid unnecessary complexity and achieve a clear structure. When combined with patterns like CQRS and event sourcing, it can produce flexible, scalable systems that truly speak the language of the domain.