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…
I used Git for two years. Every single day. But I never really knew what it was doing. I knew git commit. I knew git push. I knew that sick feeling when git merge broke everything. But if someone asked…
The Bill Nobody Expected I remember that day clearly. A teammate opened the cloud bill. Nobody spoke. Month one — $800. Fine. Normal. Month two — $1,900. Strange. Month three — $2,800. Nobody knew why. The app was the same.…
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…
Last quarter, a SaaS startup crossed 100K daily users. Everything looked fine in staging. But in production: They already had a load balancer. The problem wasn’t having one. The problem was choosing the wrong type. They used a Layer 4…