# **The Accidental CTO**



## **How I Scaled from Zero to a Million Stores on Dukaan, Without a CS 
I never set out to be a CTO. In fact, I didn’t even have a computer science degree. But somewhere between firefighting server crashes at 3 a.m. and obsessing over replication lag graphs, I found myself building systems that would eventually power over a **million online stores** at Dukaan.

This book, *The Accidental CTO*, is my behind-the-scenes account of that journey. It’s not a dry academic manual filled with abstract diagrams. Instead, it’s a story-driven handbook — one that mixes late-night startup battles with the **hard system design lessons** that only come from being in the trenches.

From scaling a scrappy MVP to running massive distributed pipelines, I’ll take you through the challenges we faced and the decisions that made (or nearly broke) us.

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### What You’ll Learn Inside

* **Scaling applications**: How we went from thousands to millions of users without falling apart.
* **Replication, sharding, caching, queues**: When to use them, when *not* to, and what tradeoffs they carry.
* **Observability as survival**: Why metrics, logs, traces, SLAs, and SLOs aren’t optional — they’re lifelines.
* **Resilience engineering**: Circuit breakers, retries, graceful degradation — designing for failure, not against it.
* **The hidden costs of cloud**: Why at scale, your AWS bill can become your biggest investor, and when it makes sense to go self-hosted.
* **The consistency/availability/latency triangle**: Why you can never fully win, and how to navigate the tradeoffs in real systems.

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### Why I Wrote This Book

I didn’t want to write another "theory of distributed systems" book. There are already plenty of those.

What I wanted to share is the **practical side** of system design — the part you only learn when a real company, with real customers and real money at stake, is on fire. The part where you’re not solving toy interview questions but dealing with:

* angry merchants refreshing dashboards,
* Kafka pipelines silently choking on one bad partition,
* a database replica 10 minutes behind and nobody knowing why.

This is the stuff no textbook teaches you.

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### Who This Book Is For

Whether you’re a **software engineer**, **architect**, or **startup founder**, I wrote this book to help you see distributed systems not as academic puzzles, but as **living, evolving machines** that you can actually build, operate, and grow.

If you’ve ever wondered *how real companies actually scale* — not in theory, but in practice — this is my candid, first-hand story.

And maybe, just maybe, you’ll find a bit of yourself in *The Accidental CTO*.