Docker Was Great. Until It Wasn’t. We had Docker. Everything was running in containers. Life was good. Then the product grew. We had 12 containers running. Then 40. Then 80. One container crashed at 2am. Nobody knew. Users were getting…
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…