Comparison of Express with other Node.js frameworks

Express is one of the most popular web frameworks in the Node.js ecosystem, known for its lightweight and flexible nature. Compared to other Node.js frameworks, Express has unique advantages in middleware handling, routing design, and community support, but it also has limitations in terms of performance or functionality. The following provides a comparative analysis across multiple dimensions.

Core Design Philosophy Comparison

Express adopts a minimalist design philosophy, with its core code providing only basic routing and middleware functionality. For example, a basic Express server requires just a few lines of code:

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

app.get('/', (req, res) => {
  res.send('Hello World');
});

app.listen(3000);

In contrast, Koa improves middleware flow control with async/await, while NestJS adopts a modular architecture. Fastify focuses on performance optimization, with benchmarks showing it handles requests about 30% faster than Express.

Middleware Mechanism Differences

Express uses a linear middleware pipeline, with manual flow control via next():

app.use((req, res, next) => {
  console.log('Middleware 1');
  next();
});

app.use((req, res, next) => {
  console.log('Middleware 2');
  next();
});

Koa's onion model supports finer-grained flow control, allowing middleware to handle both request and response phases:

app.use(async (ctx, next) => {
  console.log('Enter 1');
  await next();
  console.log('Exit 1');
});

Routing System Comparison

Express's routing system supports dynamic parameters and regex matching:

app.get('/users/:id', (req, res) => {
  res.send(`User ID: ${req.params.id}`);
});

Fastify adopts schema-based route declarations, providing automatic request validation:

fastify.get('/users/:id', {
  schema: {
    params: {
      id: { type: 'number' }
    }
  },
  handler: (request) => `User ID: ${request.params.id}`
});

Performance Benchmarking

According to TechEmpower benchmarks (Round 19):

• Fastify handles ~15,000 requests per second
• Express ~9,500 requests
• Koa ~11,000 requests
• NestJS (Express adapter) ~8,500 requests

In terms of memory usage, an Express application requires about 30MB at startup, while Fastify needs only around 20MB.

Ecosystem Expansion

Express has the richest middleware libraries:

• Authentication: Passport.js
• Templating engines: Pug/EJS
• Static files: express.static
• Error handling: express-error-handler

NestJS provides out-of-the-box functionality via decorators:

@Controller('users')
export class UsersController {
  @Get(':id')
  getUser(@Param('id') id: string) {
    return { userId: id };
  }
}

Type Support and Development Experience

Native Express lacks type support and requires additional installation of @types/express. NestJS and Fastify offer first-class TypeScript integration:

// Fastify example
interface IQuerystring {
  name: string;
}

fastify.get<{ Querystring: IQuerystring }>('/search', (request) => {
  return `Searching for ${request.query.name}`;
});

Enterprise-Level Feature Support

For complex applications, Express requires manual middleware composition:

• Dependency injection: Requires inversify
• Microservices: Requires RabbitMQ/Socket.io
• ORM integration: Separate configuration for Sequelize/TypeORM

In contrast, NestJS includes these features natively:

@Injectable()
export class UserService {
  constructor(@InjectRepository(User) private userRepository) {}
}

Learning Curve and Documentation Quality

Express's API documentation covers only core methods, while actual development requires consulting third-party resources. Fastify's documentation details performance optimization techniques, and NestJS's documentation includes complete architecture diagrams and usage examples.

Deployment and Operational Considerations

Express applications typically require the following for deployment:

npm install --production
NODE_ENV=production node server.js

NestJS projects, however, offer build optimization via CLI tools:

nest build --webpack

Community Activity Statistics

2023 npm download comparisons:

• Express: ~25 million weekly downloads
• Koa: ~2 million
• Fastify: ~800,000
• NestJS: ~600,000

GitHub star counts:

• Express: 62k
• Koa: 34k
• Fastify: 28k
• NestJS: 60k

Practical Project Selection Recommendations

For small API services, prioritize Express or Fastify. For large systems requiring long-term maintenance, NestJS is recommended due to its layered architecture, which facilitates team collaboration. For high-concurrency scenarios, test Koa's asynchronous middleware model and Fastify's performance.