02-modular-project-structure

To organize a backend by domain, create one folder per business area under the source root and place its controllers, services, repositories, DTOs, entities, and tests together to enforce clear module boundaries and scalable clarity.

Domain-driven modular architecture is a structure that clarifies boundaries by keeping all related controllers, services, repositories, and tests in a single domain folder, allowing teammates to immediately understand where requests enter and business rules live.

Reorganize a monolith into domain-per-domain modules by creating a folder for each business domain with a single public entry point, grouping transport, application, domain, and infrastructure subfolders to enforce strict cross-cutting boundaries.

Yes, backend module scaffolding can enforce a single public entry point per domain, ensuring that all external requests route through one designated boundary while keeping internal services and repositories encapsulated.

You need to add transport, application, domain, and infrastructure subfolders when your project grows in complexity, allowing scalable depth by further separating request handling, business rules, and data access within each domain module.

The best way to separate cross-cutting concerns in a domain-first backend is to keep them in shared layers outside the domain modules, ensuring each domain folder only contains its specific controllers, services, repositories, and tests.