NestJS Architecture for Operational Products

The first mistake teams make with NestJS is treating it like a folder structure problem. It is not. It is a decision-making problem.

The pattern

export class CreateProjectUseCase {
  constructor(private readonly projectsRepository: ProjectsRepository) {}
 
  async execute(input: CreateProjectInput) {
    const project = await this.projectsRepository.create(input)
    return { project }
  }
}

The goal is to make the feature boundary obvious. Controllers stay thin, use cases own intent, and repositories isolate storage details.