Exploring API design, Redis caching, database capacity, horizontal scaling, and asynchronous analytics.

System design has always seemed like one of those skills that becomes easier only when you start building systems on paper.

So, I decided to start practicing High-Level Design (HLD) by designing a familiar application: a URL shortener.

At first glance, a URL shortener looks simple. You provide a long URL, receive a short link, and redirect users when they visit it.

But what happens when millions of users create links and billions of redirects need to be processed? How do we keep redirects fast? How do we handle traffic spikes? And how do we collect analytics without slowing down the redirect path?

In this article, I'll walk through my first-pass design, the reasoning behind the architecture, and the trade-offs I need to understand better.

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