LLD Foundations: Coupling vs Cohesion (How to Judge Whether Your Design Is Actually Good)

The article explains cohesion and coupling as key ways to judge whether a software design is well structured.

It contrasts a bloated OrderService with a refactored set of focused services, including PaymentService, NotificationService, and InvoiceService.

High cohesion and low coupling create clearer responsibilities and fewer dependencies between components.

The example shows how service decomposition and an OrderOrchestrator can improve maintainability, testing, and change isolation.

The concepts align with SOLID principles, especially single responsibility and cleaner dependency boundaries.