Express.js vs NestJS: Which Node.js Framework Should You Choose in 2026?

Choosing the wrong framework does not kill a project on day one. It kills it on month six, when the codebase has grown beyond what the original structure can support. Express.js and NestJS are both excellent Node.js frameworks, but they represent fundamentally different philosophies about how backend applications should be built.

Express is minimal and unopinionated. It gives you a request pipeline and gets out of the way. NestJS is structured and opinionated, borrowing Angular's module system and bringing TypeScript-first dependency injection to the backend. Understanding the tradeoffs between them is the difference between shipping fast now and scaling cleanly later.

This guide walks through architecture, TypeScript support, scalability, testing, and deployment — with code examples — so you can make the right call for your project.

Quick Comparison

Architecture

Express: Maximum Flexibility

Express gives you a minimal HTTP server abstraction. You define routes and chain middleware functions. There is no prescribed folder structure, no module system, no dependency injection container. The framework trusts you to make those decisions.

This is powerful in small projects. A fully functional REST API in Express can live in a single file:

const express = require('express');
const app = express();

app.use(express.json());

app.get('/users', (req, res) => {
  res.json([{ id: 1, name: 'Alice' }]);
});

app.listen(3000);

The problem surfaces in larger projects. Without enforced conventions, teams naturally drift toward inconsistent patterns. Route handlers accumulate business logic. Files grow to thousands of lines. Refactoring becomes expensive.

NestJS: Enforced Structure

NestJS introduces a module system directly inspired by Angular. Every feature is encapsulated in a module that declares its controllers and providers. Controllers handle HTTP routing. Services hold business logic. Dependency injection wires them together.

This structure is not optional. It is the framework. You can bend it, but you cannot avoid it.

src/
  users/
    users.controller.ts
    users.service.ts
    users.module.ts
  app.module.ts
  main.ts

For a team working on a shared codebase, this predictability is worth more than the initial setup cost. You always know where business logic lives, how to add a feature, and how to test a unit in isolation.

TypeScript Support

Express

Express was written before TypeScript was mainstream. You can use TypeScript with Express, but it requires setup: installing @types/express, configuring tsconfig.json, and making deliberate choices about how to type request bodies, params, and responses.

import express, { Request, Response } from 'express';

const app = express();
app.use(express.json());

interface User {
  id: number;
  name: string;
}

app.get('/users', (req: Request, res: Response<User[]>) => {
  res.json([{ id: 1, name: 'Alice' }]);
});

This works well, but the typing discipline is entirely on the developer. There is nothing in the framework that enforces it.

NestJS

NestJS was built with TypeScript. Every decorator, every interface, every lifecycle hook is typed. The framework uses TypeScript metadata (via reflect-metadata) to power its dependency injection system — which means TypeScript is not optional, it is load-bearing.

import { Controller, Get } from '@nestjs/common';
import { UsersService } from './users.service';
import { User } from './user.entity';

@Controller('users')
export class UsersController {
  constructor(private readonly usersService: UsersService) {}

  @Get()
  findAll(): Promise<User[]> {
    return this.usersService.findAll();
  }
}

The return type is enforced by the service method signature. The controller does not need to know how users are fetched — it only calls the service. This separation is enforced by the module system, not by convention.

Scalability and Structure

Express scales well horizontally — it is fast and stateless by nature. But organizational scalability is the real challenge in large projects. Without discipline, Express codebases become hard to navigate and harder to onboard new developers onto.

NestJS solves this by making structure non-negotiable. Every feature module is self-contained. Adding a new resource means adding a new module with a consistent interface. This makes large codebases navigable because the folder structure communicates intent.

For teams of more than three or four backend developers, the overhead of enforcing Express conventions manually tends to exceed the overhead of learning NestJS conventions once.

Code Examples: Equivalent CRUD Endpoint

To make the comparison concrete, here is the same endpoint — creating a user — implemented in both frameworks.

Express

// routes/users.js
const express = require('express');
const router = express.Router();

const users = [];

router.post('/', (req, res) => {
  const { name, email } = req.body;

  if (!name || !email) {
    return res.status(400).json({ error: 'Name and email are required' });
  }

  const user = { id: users.length + 1, name, email };
  users.push(user);

  res.status(201).json(user);
});

module.exports = router;

// app.js
const express = require('express');
const usersRouter = require('./routes/users');

const app = express();
app.use(express.json());
app.use('/users', usersRouter);

app.listen(3000);

NestJS

// users/create-user.dto.ts
import { IsString, IsEmail } from 'class-validator';

export class CreateUserDto {
  @IsString()
  name: string;

  @IsEmail()
  email: string;
}

// users/users.service.ts
import { Injectable } from '@nestjs/common';
import { CreateUserDto } from './create-user.dto';

@Injectable()
export class UsersService {
  private users = [];

  create(createUserDto: CreateUserDto) {
    const user = { id: this.users.length + 1, ...createUserDto };
    this.users.push(user);
    return user;
  }
}

// users/users.controller.ts
import { Controller, Post, Body } from '@nestjs/common';
import { UsersService } from './users.service';
import { CreateUserDto } from './create-user.dto';

@Controller('users')
export class UsersController {
  constructor(private readonly usersService: UsersService) {}

  @Post()
  create(@Body() createUserDto: CreateUserDto) {
    return this.usersService.create(createUserDto);
  }
}

// users/users.module.ts
import { Module } from '@nestjs/common';
import { UsersController } from './users.controller';
import { UsersService } from './users.service';

@Module({
  controllers: [UsersController],
  providers: [UsersService],
})
export class UsersModule {}

The NestJS version is more code. It also has automatic validation via class-validator, a clearly separated service layer, and a module boundary that makes the feature portable and testable in isolation. The tradeoff is explicit.

Testing

Express

Express does not provide testing utilities. You wire up Jest or Mocha, use supertest for HTTP-level integration tests, and mock dependencies manually. This works fine, but mocking deeply nested dependencies requires deliberate effort.

// users.test.js
const request = require('supertest');
const app = require('./app');

describe('POST /users', () => {
  it('creates a user', async () => {
    const res = await request(app)
      .post('/users')
      .send({ name: 'Alice', email: '[email protected]' });

    expect(res.status).toBe(201);
    expect(res.body.name).toBe('Alice');
  });
});

NestJS

NestJS ships with a Test module that creates an isolated application context for unit and integration tests. Because every dependency is injected, you can swap any provider for a mock in tests without touching the implementation.

// users.controller.spec.ts
import { Test, TestingModule } from '@nestjs/testing';
import { UsersController } from './users.controller';
import { UsersService } from './users.service';

describe('UsersController', () => {
  let controller: UsersController;
  let service: UsersService;

  beforeEach(async () => {
    const module: TestingModule = await Test.createTestingModule({
      controllers: [UsersController],
      providers: [
        {
          provide: UsersService,
          useValue: { create: jest.fn().mockReturnValue({ id: 1, name: 'Alice' }) },
        },
      ],
    }).compile();

    controller = module.get<UsersController>(UsersController);
    service = module.get<UsersService>(UsersService);
  });

  it('calls the service with the correct DTO', () => {
    const dto = { name: 'Alice', email: '[email protected]' };
    controller.create(dto);
    expect(service.create).toHaveBeenCalledWith(dto);
  });
});

The dependency injection system and the testing module are designed together. Unit tests in NestJS are fast and isolated by default.

Deploying Express and NestJS on Out Plane

Both frameworks run as standard Node.js processes and deploy identically on Out Plane. The platform handles containerization, routing, scaling, and environment variable management — you push code and the infrastructure configures itself.

For detailed deployment walkthroughs:

• How to deploy an Express.js application on Out Plane
• How to deploy a NestJS application on Out Plane

Both guides cover production configuration, environment setup, and scaling considerations specific to each framework.

When to Choose Express

Express is the right choice when:

• You are building a small API, a prototype, or a proof of concept
• You are building a single-purpose microservice that does not need an elaborate structure
• Your team is small and can maintain conventions informally
• You are integrating with an existing Express codebase
• You want maximum flexibility in how you organize your application
• You need to ship something in hours, not days

Express remains the most widely used Node.js framework for good reason. Its simplicity is an asset in the right context.

When to Choose NestJS

NestJS is the right choice when:

• You are building an enterprise-grade application that will grow over time
• Your team has more than a few backend developers working in the same codebase
• You want TypeScript to be a first-class part of your architecture, not an afterthought
• You need built-in support for microservices, WebSockets, or GraphQL without additional glue code
• Testability and separation of concerns are non-negotiable requirements
• You want new team members to understand the codebase structure immediately

The learning curve is real, but the investment compounds. Every new feature follows the same pattern, which keeps large codebases maintainable.

Summary

Express and NestJS are not competitors in the way that, say, React and Vue are. They target different problem spaces.

Express gives you a foundation and trusts you to build what you need on top of it. That trust is earned quickly in small projects and becomes a liability in large ones. NestJS gives you a complete architectural framework and asks you to work within it. That constraint is a burden early and a benefit permanently.

For greenfield projects in 2026, the default recommendation leans toward NestJS if TypeScript, team size, or long-term maintainability is a concern. For fast iteration, microservices, or projects where simplicity is a feature, Express is still one of the best tools available.

Ready to deploy? Follow the step-by-step guide for your framework: Express deployment guide | NestJS deployment guide. Both run on Out Plane with no additional configuration. Get started with Out Plane.