nestjs-conventions

---

name: nestjs-conventions description: Backend conventions for NestJS projects: modules, controllers, services, DTOs, migrations, structure. Use when implementing or reviewing code in NestJS backends.

NestJS Conventions

When working in backend/ (or NestJS app root), follow these conventions:

• Structure: Feature-based modules. Each feature: *.module.ts, *.controller.ts, *.service.ts, entities, dto/. No business logic in controllers.
• DTOs: Always use DTOs with class-validator; separate create/update/response. User-facing messages in English.
• Migrations: Never create migration files manually. Use TypeORM CLI: npm run typeorm:generate -- src/database/migrations/DescriptiveName. Entities drive schema.
• Guards/Interceptors: Use common guards and interceptors; constructor injection.
• Config: @nestjs/config; typed config; no hardcoded secrets.
• Errors: NestJS exception filters; consistent error format; English messages.
• IAC: Do not run CDK deploy from backend work unless project-specific; use AWS CLI for actual AWS changes.

Reference project rules and structure docs for full details.