Hayden

If you’ve been building backends, you’ve probably experienced how project maintenance becomes increasingly difficult as the codebase grows. An Express project that started small can quickly turn into spaghetti code, and inconsistent coding styles across team members make code reviews challenging.

In 2025, there’s a framework that addresses these pain points: NestJS. Since its debut in 2017, it has earned over 67,000 stars on GitHub and continues to be loved by developers worldwide.

 

NestJS

 

 

1. What Exactly is NestJS?

NestJS is a Node.js-based backend framework. Simply put, it’s a tool that helps you build efficient and scalable server applications.

“Why not just use Express for Node.js?” you might ask. Express is indeed an excellent framework. However, NestJS builds on top of Express (or Fastify) while taking things to the next level.

To put it in perspective:

  • Express = Minimalist Flask (Python)
  • NestJS = Structured Django (Python) or Spring (Java)

While Express offers freedom, NestJS provides clear structure and conventions. Like LEGO blocks where each piece has its designated place, it enables teams to maintain consistent code even with multiple contributors.

 

Express.js? – Node.js Backend Web Server Framework

 

 

2. Why Choose NestJS in 2025?

Trusted by Enterprises

In 2025, NestJS isn’t just a trendy framework. Many global companies use NestJS in production. From startups to large enterprises, organizations of all sizes trust NestJS.

Future-Ready Roadmap

The NestJS team announced an exciting roadmap at the 2024 developer conference:

  • 2025: Server Components support for frontend-backend component sharing
  • 2026: Native WebAssembly support for performance enhancement
  • 2027: AI-assisted development toolchain for automatic code generation

They’re not just focusing on the present but preparing for future technological trends.

Continuous Updates

Version 10, released in 2024, added native Prisma support and GraphQL Federation 2.0, with version 11 on the horizon. The NestJS team secured Series A funding and committed to maintenance until at least 2030.

 

 

3. Core Advantages of NestJS

TypeScript by Default

NestJS was designed with TypeScript in mind from the start. Unlike other frameworks that say “we can support TypeScript too,” NestJS was built assuming you’d use TypeScript.

Why does this matter? With TypeScript, you get:

  • Early detection of type errors during development
  • More accurate IDE autocompletion
  • Easier code comprehension for team members

You can use JavaScript if needed, but to fully appreciate NestJS, TypeScript is recommended.

Structured Architecture

NestJS draws heavy inspiration from Java’s Spring framework, providing clear structure through Modules, Controllers, Services, and Repositories.

Example Project Structure:
src/
└── users/
    ├── users.controller.ts    (Controller: routing and request handling)
    ├── users.service.ts       (Service: business logic)
    ├── users.module.ts        (Module: dependency management)
    ├── dto/                   (DTO: data transfer objects)
    └── entities/              (Entity: database models)

With clear roles for each file, new team members can quickly understand the codebase. According to the official 2024 developer survey, code maintainability improved by 40% and onboarding time for new developers decreased by 50% on average.

Role of Each Component:

  • Controller: Receives client requests and returns responses
  • Service: Handles actual business logic (a type of Provider)
  • Module: Groups related functionality together
  • Provider: Injectable classes (services, repositories, etc.)
  • Repository: Direct communication with the database

Dependency Injection (DI)

While it might sound complex initially, it’s a pattern that makes your code cleaner.

// Example: Injecting Service into Controller
@Controller('users')
export class UsersController {
  constructor(private readonly usersService: UsersService) {}
  
  @Get()
  findAll() {
    return this.usersService.findAll();
  }
}

This creates loose coupling between components, making testing easier and future modifications simpler.

Clean Code with Decorators

NestJS heavily utilizes decorators (starting with @), making code much more readable.

@Controller('cats')  // This class handles /cats routes
export class CatsController {
  
  @Get()  // Handles GET requests
  findAll() {
    return 'This returns all cats';
  }
  
  @Post()  // Handles POST requests
  create(@Body() createCatDto: CreateCatDto) {
    return 'This creates a new cat';
  }
}

Without complex routing configuration, decorators make it immediately clear what each function does.

Powerful CLI Tool

The NestJS Command Line Interface (CLI) is incredibly convenient. A few commands automatically generate necessary files.

nest g controller users  # Generate Controller
nest g service users     # Generate Service
nest g module users      # Generate Module

Files are automatically created with necessary imports included. This reduces repetitive work and speeds up development.

Rich Ecosystem

NestJS provides or easily integrates various features:

  • Databases: TypeORM, Prisma, Mongoose, etc.
  • Authentication: Passport, JWT, etc.
  • Validation: class-validator, class-transformer
  • Documentation: Automatic Swagger/OpenAPI generation
  • Testing: Jest comes built-in
  • Real-time: WebSocket, Socket.io
  • Microservices: RabbitMQ, Kafka, Redis, etc.

Most features you need can be found in the official documentation.

 

 

4. What About Performance?

“Won’t it be slow running on top of Express?” you might wonder.

According to 2024 benchmark tests:

Metric NestJS Express Difference
Requests per second (QPS) 8,500 9,200 ~8%
Memory usage 15% higher than Express Baseline –
Scalability Linear growth with clustering Same –

The performance difference is minimal. For most enterprise applications, this slight difference is more than offset by improved development efficiency. Plus, it’s far more memory-efficient than Spring Boot (about 1/5 of its memory usage).

 

 

5. Getting Started with NestJS – Practical Guide

Let’s get hands-on with NestJS. It’s simpler than you think!

Prerequisites

First, you need Node.js installed. Download the LTS version from the official Node.js website. LTS (Long Term Support) is the stable, production-ready version.

After installation, verify in your terminal:

node --version
npm --version

If versions display, you’re ready.

Step 1: Install NestJS CLI

Install the NestJS CLI globally:

npm i -g @nestjs/cli

The -g flag means global installation, allowing you to use the nest command from any directory.

After installation:

nest --version

If a version appears, success!

Step 2: Create a New Project

Run this command from your desired directory:

nest new my-project

You’ll be prompted to choose a package manager:

? Which package manager would you ❤️  to use?
❯ npm
  yarn
  pnpm

Choose npm (or your preference). After a brief wait, your project will be automatically generated.

Step 3: Explore Project Structure

Navigate to your project folder:

cd my-project

The basic structure looks like this:

my-project/
├── src/
│   ├── app.controller.ts       # Controller: HTTP request handling
│   ├── app.controller.spec.ts  # Controller test file
│   ├── app.service.ts          # Service: business logic
│   ├── app.module.ts           # Module: root module
│   └── main.ts                 # Entry Point: application start
├── test/                       # Test files
├── node_modules/               # Installed packages
├── package.json                # Project info and dependencies
├── tsconfig.json               # TypeScript configuration
└── nest-cli.json               # NestJS CLI configuration

Step 4: Start the Server

Run the server in development mode:

npm run start:dev

The start:dev command automatically restarts the server when code changes are detected, similar to using nodemon with Express.

When the server starts, you’ll see:

[Nest] Application successfully started
[Nest] Listening on http://localhost:3000

Open your browser to http://localhost:3000 to see “Hello World!”. Congratulations! Your first NestJS server is running.

Step 5: Build Your First API

Let’s create a simple Cats API.

Generate Controller:

nest g controller cats

This creates src/cats/cats.controller.ts.

Generate Service:

nest g service cats

This creates src/cats/cats.service.ts.

Edit cats.service.ts:

import { Injectable } from '@nestjs/common';

@Injectable()
export class CatsService {
  private readonly cats: string[] = ['Persian', 'Siamese', 'Maine Coon'];

  findAll(): string[] {
    return this.cats;
  }

  create(cat: string) {
    this.cats.push(cat);
    return cat;
  }
}

Edit cats.controller.ts:

import { Controller, Get, Post, Body } from '@nestjs/common';
import { CatsService } from './cats.service';

@Controller('cats')
export class CatsController {
  constructor(private readonly catsService: CatsService) {}

  @Get()
  findAll(): string[] {
    return this.catsService.findAll();
  }

  @Post()
  create(@Body('name') name: string) {
    return this.catsService.create(name);
  }
}

Now test your API:

GET Request: Visit http://localhost:3000/cats in your browser → Returns ["Persian", "Siamese", "Maine Coon"]

POST Request: (using Postman or curl)

curl -X POST http://localhost:3000/cats \
  -H "Content-Type: application/json" \
  -d '{"name":"Bengal"}'

→ Adds a new cat!

Step 6: Add Data Validation

In production, you need to validate user input. NestJS makes it easy to use class-validator.

Install packages:

npm install class-validator class-transformer

Create DTO:

Create src/cats/dto/create-cat.dto.ts:

import { IsString, IsNotEmpty, MinLength } from 'class-validator';

export class CreateCatDto {
  @IsString()
  @IsNotEmpty()
  @MinLength(2)
  name: string;
}

Add global pipe to main.ts:

import { ValidationPipe } from '@nestjs/common';
import { NestFactory } from '@nestjs/core';
import { AppModule } from './app.module';

async function bootstrap() {
  const app = await NestFactory.create(AppModule);
  app.useGlobalPipes(new ValidationPipe());  // Add global validation pipe
  await app.listen(3000);
}
bootstrap();

Update Controller:

@Post()
create(@Body() createCatDto: CreateCatDto) {
  return this.catsService.create(createCatDto.name);
}

Now invalid data automatically returns validation errors!

 

 

6. Why Learning NestJS is Valuable

Spring Developers Will Feel at Home

If you have Java Spring experience, NestJS uses nearly identical concepts:

Spring NestJS
@Controller @Controller
@Service @Injectable
@Autowired constructor injection
@RequestMapping @Get, @Post, etc.
@Valid ValidationPipe

For developers transitioning from Spring to Node.js, NestJS is an excellent choice.

Familiar to Angular Developers

NestJS draws heavy inspiration from Angular. Concepts like Providers, decorators, and dependency injection are nearly identical, making the learning curve gentle for Angular developers.

Express Developers Can Migrate Gradually

Working with an existing Express project? No worries. Since NestJS uses Express internally, you can continue using existing Express middleware and libraries.

// Using Express middleware
import * as cookieParser from 'cookie-parser';

async function bootstrap() {
  const app = await NestFactory.create(AppModule);
  app.use(cookieParser());  // Use Express middleware directly
  await app.listen(3000);
}

 

What is Angular? Google’s JavaScript Frontend Framework

 

 

7. Real-World Use Cases for NestJS

REST API Servers

The most common use case. Suitable for any web application requiring CRUD operations.

  • E-commerce backends
  • Blog systems
  • Admin panel APIs
  • Mobile app backends

GraphQL APIs

NestJS natively supports GraphQL. If you want to solve REST API’s over-fetching/under-fetching problems, consider GraphQL.

npm install @nestjs/graphql @nestjs/apollo graphql apollo-server-express

Check the official GraphQL guide for easy setup.

Microservices

For large systems split into smaller services, use NestJS’s microservices features.

Supported transport layers:

  • TCP
  • Redis
  • RabbitMQ
  • Kafka
  • NATS
  • MQTT

Real-time Applications

For chat, notifications, or real-time dashboards, leverage WebSocket support.

npm install @nestjs/websockets @nestjs/platform-socket.io

 

 

8. Useful Tips

Automatic Swagger Documentation

Don’t want to write API documentation manually? NestJS automatically generates Swagger.

npm install @nestjs/swagger swagger-ui-express

// main.ts
import { SwaggerModule, DocumentBuilder } from '@nestjs/swagger';

async function bootstrap() {
  const app = await NestFactory.create(AppModule);
  
  const config = new DocumentBuilder()
    .setTitle('Cats API')
    .setDescription('The cats API description')
    .setVersion('1.0')
    .build();
  const document = SwaggerModule.createDocument(app, config);
  SwaggerModule.setup('api', app, document);  // Access docs at /api
  
  await app.listen(3000);
}

Now visit http://localhost:3000/api for beautiful auto-generated API documentation!

Environment Variable Management

To manage environment variables with .env files:

npm install @nestjs/config

// app.module.ts
import { ConfigModule } from '@nestjs/config';

@Module({
  imports: [
    ConfigModule.forRoot({
      isGlobal: true,  // Use globally
    }),
  ],
})
export class AppModule {}

Now access .env values via process.env.VARIABLE_NAME.

Database Connection (TypeORM Example)

To use PostgreSQL, MySQL, etc.:

npm install @nestjs/typeorm typeorm pg

// app.module.ts
import { TypeOrmModule } from '@nestjs/typeorm';

@Module({
  imports: [
    TypeOrmModule.forRoot({
      type: 'postgres',
      host: process.env.DB_HOST,
      port: 5432,
      username: process.env.DB_USERNAME,
      password: process.env.DB_PASSWORD,
      database: process.env.DB_NAME,
      entities: [__dirname + '/**/*.entity{.ts,.js}'],
      synchronize: true,  // Set to false in production
    }),
  ],
})
export class AppModule {}

Authentication with Guards

To create APIs requiring login, use Guards:

import { Injectable, CanActivate, ExecutionContext } from '@nestjs/common';

@Injectable()
export class AuthGuard implements CanActivate {
  canActivate(context: ExecutionContext): boolean {
    const request = context.switchToHttp().getRequest();
    // Implement authentication logic here
    return validateRequest(request);
  }
}

Apply to Controller:

@Controller('cats')
@UseGuards(AuthGuard)  // Apply authentication to all methods
export class CatsController {
  // ...
}

 

 

9. Considerations When Using NestJS

Learning Curve Exists

Compared to Express, there are more concepts to learn: Dependency Injection, Decorators, and Module System. Especially if you’re not familiar with TypeScript, the initial learning phase can be challenging.

However, once mastered, these concepts significantly improve code quality, making the investment worthwhile long-term.

Overkill for Small Projects

For simple prototypes or very small projects, Express might be better. NestJS shines as projects grow and teams expand.

Use @nestjs/mapped-types

When modifying DTOs, use @nestjs/mapped-types instead of TypeScript’s built-in Partial<T> or Omit<T> to preserve decorator metadata.

npm install @nestjs/mapped-types

import { PartialType } from '@nestjs/mapped-types';

export class UpdateCatDto extends PartialType(CreateCatDto) {}

 

 

10. Resources for Deeper Learning

Official Documentation

The NestJS official documentation is excellently organized with abundant code examples that are easy to follow.

Official GitHub

Explore source code, stay updated through issues and discussions at the NestJS GitHub repository.

Community Resources

Learning Paths

For a structured learning approach, check out the 2025 NestJS Roadmap, organized from beginner to senior level.

 

 

In 2025, NestJS has evolved beyond a trendy framework into a proven enterprise-grade solution. With structured architecture, native TypeScript support, a rich ecosystem, and an active community, it’s an excellent choice for serious backend development.

Initially, it may seem more complex than Express. However, as projects grow and teams expand, you’ll appreciate the structure and conventions NestJS provides. Especially in collaborative environments, consistent code style and clear separation of concerns significantly boost development productivity.

Whether you’re starting backend development with Node.js or looking to level up from Express, now is a great time to learn NestJS. With support guaranteed until 2030 and continuous improvements, it’s a solid investment.

Start today with nest new my-first-project. A new world of backend development awaits you!

 

 

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