The article explains that domain services are not optional in DDD but become necessary when aggregate roots cannot contain certain business rules, such as those requiring external data, batch processing, or rules that don’t belong to a single aggregate, and outlines principles for their proper use.
Using a real‑world salary‑calculation module, the article shows how to separate Domain Services, Application Services, and Infrastructure in DDD, explains the responsibilities of each layer, provides concrete code refactorings, and offers practical questions to decide where new logic belongs.
This article delves into the tactical design of Domain‑Driven Design, explaining core building blocks such as entities, value objects, aggregates, domain events, repositories, application services, and domain services, and shows how they help keep business logic centralized and expressive.
This article explains how application services act as a façade for domain models, outlines key design principles, shows practical Go/Java implementation patterns, discusses transaction propagation and security handling, and provides concrete best‑practice recommendations for building thin, framework‑agnostic backend services.
This article explains how to identify and refactor typical “流水账” (spaghetti) code in a checkout API by applying Domain‑Driven Design layers—splitting responsibilities into Interface, Application, and Domain layers, using CQE objects, DTO assemblers, and anti‑corruption facades to achieve clear, maintainable modules.
