NestJS vs Express vs Fastify comparison

Introduction

These are popular tools to build web servers in JavaScript. Knowing their differences helps you pick the right one for your project.

You want a simple and minimal server setup quickly.

You need a structured and scalable backend with built-in features.

You want a very fast server that handles many requests efficiently.

You are learning backend development and want to understand different approaches.

You want to compare performance and developer experience before choosing.

Syntax

NestJS

const express = require('express');
const fastify = require('fastify')();
import { NestFactory } from '@nestjs/core';

Express uses simple functions and middleware.

Fastify uses plugins and schemas for speed.

Examples

Express example: simple route and server start.

NestJS

const express = require('express');
const app = express();
app.get('/', (req, res) => res.send('Hello from Express!'));
app.listen(3000);

Fastify example: fast and async route handler.

NestJS

const fastify = require('fastify')();
fastify.get('/', async (request, reply) => {
  return 'Hello from Fastify!';
});
fastify.listen(3000);

NestJS example: uses decorators and modules for structure.

NestJS

import { NestFactory } from '@nestjs/core';
import { Module, Controller, Get } from '@nestjs/common';

@Controller()
class AppController {
  @Get()
  getHello() {
    return 'Hello from NestJS!';
  }
}

@Module({
  controllers: [AppController],
})
class AppModule {}

async function bootstrap() {
  const app = await NestFactory.create(AppModule);
  await app.listen(3000);
}
bootstrap();

Sample Program

This NestJS app shows a simple server with one route. It uses decorators to define the controller and route. When you visit the root URL, it returns a greeting.

NestJS

import { NestFactory } from '@nestjs/core';
import { Module, Controller, Get } from '@nestjs/common';

@Controller()
class AppController {
  @Get()
  getHello() {
    return 'Hello from NestJS!';
  }
}

@Module({
  controllers: [AppController],
})
class AppModule {}

async function bootstrap() {
  const app = await NestFactory.create(AppModule);
  await app.listen(3000);
  console.log('Server running on http://localhost:3000');
}
bootstrap();

Important Notes

Express is easy to learn and has many plugins but less structure.

Fastify is very fast and good for high performance but has a steeper learning curve.

NestJS adds structure and features like dependency injection, good for large apps.

Summary

Express is simple and flexible for quick setups.

Fastify focuses on speed and efficiency.

NestJS provides a structured framework with modern features.