NestJS gives Node.js the structure it needs: modules, dependency injection, and TypeScript from the ground up. But structure alone does not guarantee maintainability. The difference comes from how you draw boundaries.
We start every backend with three clear layers: authentication, public read endpoints, and admin mutations. Each domain gets its own module with DTOs validated at the boundary. Types are shared across frontend and backend through a monorepo package, which eliminates the drift that breaks integrations after a few months.