Building Scalable APIs with Node.js

Building scalable APIs requires careful consideration of architecture, security, and performance. This guide covers essential patterns for production-ready Node.js APIs.

Project Structure

Organize your code by feature:

src/
├── modules/
│   ├── users/
│   │   ├── users.controller.ts
│   │   ├── users.service.ts
│   │   ├── users.routes.ts
│   │   └── users.types.ts
│   └── posts/
├── middleware/
├── utils/
└── index.ts

Input Validation

Always validate input using libraries like Zod:

const createUserSchema = z.object({ email: z.string().email(), name: z.string().min(2), password: z.string().min(8), }); ```

Error Handling

Create consistent error responses:

class AppError extends Error {
  constructor(
    public message: string,
    public statusCode: number,
  ) {
    super(message);
  }

app.use((err, req, res, next) => { const status = err.statusCode || 500; res.status(status).json({ error: err.message }); }); ```

Rate Limiting

Protect your API from abuse:

const limiter = rateLimit({ windowMs: 15 * 60 * 1000, max: 100, });

app.use('/api', limiter); ```

Conclusion

Following these patterns will help you build APIs that can handle production traffic while remaining maintainable and secure.