System Design

Parking Lot LLD — What I Learned Building It I recently started practicing Low Level Design problems to strengthen my system design and backend thinking. The second problem I picked was the classic Parking Lot System. At first, it looked simple. But while building it, I realized these problems are less about writing code and more about: Modeling real-world systems Managing state correctly Designing scalable abstractions Avoiding bad object-oriented practices Code Repo parking lot ...

In the Previous attempt we designed an elevator system using two queues — an up queue and a down queue. But that system had some problems. It changed direction abruptly and did not respect the order of requests. To overcome this, the system has been redesigned with an active and shadow queue strategy that better mirrors how a real elevator behaves. The Requirements The requirements remain the same as the original design: ...

I have started learning low level system design and elevator is the first problem i picked up. In this i have picked the single elvator for simplicity and not get overwhelmed by it and get demotivated. So I built an elevator system. Lets improve this in stages. Not because it’s trendy. I have thought countless times standing in elevator does how it works. and after this i have my answer. ...

Introduction In modern systems, messaging queues are one of the most essential building blocks. They are the unsung heroes that help us decouple services, making our systems scalable, fault-tolerant, and efficient. Without queues, managing communication between multiple services would be chaotic and unreliable. Why Queues? The Monolithic Scenario In a monolithic architecture, all parts of the system are tightly coupled. Let’s take an example of three services connected directly: A → B → C. ...