The Interview Question That Got Me “Tell me about the CAP theorem.” I had heard the term. I said something about consistency and availability. The interviewer nodded slowly. Asked a follow-up. I stumbled. I did not get the job. Later…
😤 The Day Our Server Went Down We launched a new feature. Put it on Product Hunt. Within 20 minutes — the server was dead. Not from real users. From bots scraping our API. One IP address sent 14,000 requests…
I Was Confused Too Someone asked me in an interview — “Where would you put the API Gateway?” I said “same place as the load balancer.” The interviewer paused. Then moved on. I failed that round. Later I realized —…
🚨 The Problem I saw a login form once. No padlock. No HTTPS. I ran a quick test. The password was plain text. Anyone on the same Wi-Fi could read it. The site had been live for two years. Most…
The Problem I watched a product go from 200 users to 40,000 users in three weeks. It was a good problem to have. Until the database started choking. Page loads went from 300ms to 12 seconds. The team kept scaling…
The Problem — One Database Does Not Fit Everything A startup builds its first product. One database. Everything goes in. User accounts, orders, logs, notifications — all in one place. Traffic grows. New features arrive. The team adds a social…
The Problem — Computers Do Not Understand Names A developer types github.com into a browser. The page loads in one second. Simple. But computers do not understand names. Computers talk to each other using numbers. Every server on the internet…
The Problem — Apps That Can’t Talk Imagine a food delivery app. A customer places an order. Three things must happen at once: Simple enough. Now imagine 10,000 orders come in at once. The app sends a message to the…
Target Audience This post is for backend engineers, DevOps engineers, and anyone preparing for system design interviews who wants to understand why some apps feel instant — and others feel slow. What You Will Learn You will understand how caching…