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name: nestjs-backend-development description: Build scalable server-side applications with NestJS. Use when (1) creating a new NestJS app, (2) creating Modules, Controllers, and Services, (3) setting up Database integration (TypeORM), (4) implementing Authentication/Authorization (Custom JWT), or (5) setting up API Documentation (Swagger).

NestJS Backend Development

Build efficient, scalable Node.js server-side applications with NestJS.

Tech Stack

• NestJS 10+ (Core Framework)
• TypeScript (Language)
• TypeORM (Database ORM)
• PostgreSQL (Recommended Database)
• JWT (Authentication)
• Swagger (API Documentation)
• Jest (Testing)
• Docker (Containerization)

Quick Start

1. Create Project

Generating a new project with strict mode enabled is recommended.

Copynpm i -g @nestjs/cli
nest new my-nest-app --strict
cd my-nest-app

For detailed project setup and configuration (ConfigModule, ValidationPipe), see setup-guide.md.

2. Generate Resource

Use the CLI to generate a complete CRUD resource (Module, Controller, Service, DTOs, Entities).

Copynest g resource users

For understanding the project structure and architecture, see project-structure.md.

3. Setup Database (TypeORM)

Install TypeORM and configured it in app.module.ts.

Copynpm install --save @nestjs/typeorm typeorm pg

For complete database configuration and Entity patterns, see database.md.

Workflows

Implementing Authentication

1. Install JWT package: npm install @nestjs/jwt
2. Create AuthModule: Configure JwtModule with secrets.
3. Create AuthGuard: Implement CanActivate to verify tokens with JwtService.
4. Protect Routes: Use AuthGuard on controllers/routes.

See authentication.md for the complete implementation guide.

Creating a Robust API Endpoint

1. Define DTO: Create a class with validation decorators.
2. Create Controller Method: Use decorators (@Post, @Body) and types.
3. Implement Service Logic: Handle business logic and database interactions.
4. Add Swagger Docs: Use @ApiProperty on DTOs and @ApiOperation on controllers.

See dto-validation.md for validation patterns.

Reference Files

• setup-guide.md - CLI installation, project creation, main.ts bootstrapping, ConfigModule.
• project-structure.md - Modular architecture, folder structure, core components (Modules, Controllers, Services).
• database.md - TypeORM setup, Entity definition, Repository pattern, Transactions.
• authentication.md - Custom JWT Guard, JwtService, Auth guards, CurrentUser decorator.
• dto-validation.md - DTO creation, class-validator decorators, Pipes.

Best Practices

Architecture

• Modularization: specific features should be in their own modules (e.g., AuthModule, UsersModule).
• Dependency Injection: Always inject dependencies via constructors. Avoid hard-coding.
• Environment Variables: Never commit secrets. Use @nestjs/config and .env files.

Code Quality

• DTOs: Always use DTOs for input data validation. Do not use raw objects.
• Strict Mode: Use TypeScript strict mode.
• Async/Await: Use async/await for all asynchronous operations (DB calls).

API Design

• RESTful: Follow REST conventions (GET /users, POST /users, GET /users/:id).
• Status Codes: Return appropriate HTTP status codes (201 Created, 400 Bad Request, 404 Not Found).
• Documentation: Keep Swagger documentation up to date.