Getting into load balancing for interviews
You walk into a system design interview and they toss you a big question like, “Design a video platform” or “Build an API that handles millions of users.” My brain always jumps to the same scary thing first. What happens when traffic spikes and one server gets crushed. That’s where load balancing shows up fast.
Load balancing is basically spreading requests across multiple machines so nothing melts down. Sounds simple, but interviews make it weird because they want choices, not just the word “load balancer.” Like, do we balance at DNS level or at a reverse proxy. Do we use round robin or something smarter. What about sticky sessions, health checks, retries that accidentally double the traffic. You start pulling on one thread and suddenly there are five more.
I like thinking of it as a set of levers. You pick what you need based on the app’s behavior. Is it mostly reads, mostly writes, long connections like websockets, or tiny quick HTTP calls. And yeah, sometimes the “best” strategy is just the one that is easiest to explain clearly under pressure.
Quick ending
If you can say what problem you’re solving and why your load balancing choice fits it, you already look solid. The rest is details you can layer in as time allows.
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