Apply Domain-Driven Design (DDD) when modeling a business domain or structuring code around business logic, on the backend or the frontend. Use whenever the user is designing or refactoring a domain model, pulling business rules out of controllers or UI components, organizing a backend service or an Angular app by domain or bounded context, or mentions DDD, bounded contexts, ubiquitous language, aggregates, entities, value objects, domain events, repositories, domain or application services, anti-corruption layers, or CQRS — even if they never say "DDD". It covers strategic design and collaborative modeling (context mapping, EventStorming), tactical patterns (aggregate boundaries, invariants, value objects), and idiomatic implementation in Spring Boot/Java or Angular. Prefer it over ad-hoc modeling whenever non-trivial business rules or invariants are involved. It does not apply to plain CRUD with no business rules, UI styling, DevOps or infrastructure, database query tuning, or framework API how-to questions
2026-06-23
