Professional Middleware Development

Every request your app receives passes through middleware. It decides who gets in, what gets logged, how fast the answer comes back, and what happens when something breaks. Using Node.js 22 and Express 5, this book shows you how to build that layer properly.

It's 2 a.m. Your API is crawling. Requests are timing out. Retries are piling up and making it worse, and nobody knows which service started it.

So what went wrong?

Most of the time, the answer is hiding in the middleware: a missing timeout, a cache stampede, a token that was never checked properly.

I wrote this book so you never face that night unprepared. I'll walk you through every layer, one clear step at a time, until you can build systems that stay calm under pressure.

• Architecture: clean pipelines, the right order, error layers, and hexagonal design
• Security: JWT, OAuth2 with PKCE, mTLS, CORS, CSRF, and rate limiting
• Performance: caching, compression, streaming, WebSockets, and worker threads
• Resilience: circuit breakers, retries, bulkheads, load shedding, and graceful shutdown
• Observability: structured logs, tracing, and metrics
• Real code: dozens of tested listings, plus checklists and ready-to-use recipes

• Node.js developers who want to go beyond tutorials
• Backend and full-stack engineers building real products
• Tech leads who review architecture and security
• Anyone who wants their APIs to be safer and faster