System design interview questionEasyBasic System Component
Design a Load Balancer for Web Servers
Design a load balancer that sits in front of many web/app servers and spreads traffic so no single server melts.
Interview scope
Draw Client → Load Balancer → multiple App Servers. No Client → App direct skip of the LB.
Functional requirements
- Accept client requests and forward them to healthy backends.
- Support more than one app server instance.
- Basic health awareness (don’t send traffic to a dead box — high level is enough).
Scale and quality goals
- LB itself should not be an obvious single bottleneck you ignore.
- Adding app servers should increase capacity.
- Clients should not pick a random app IP forever by hand.
Capacity assumption
Design for this scale
Assume ~50k RPS peak across ~20 app servers (~2.5k RPS per server if even).
Practice more than a diagram
Place components on the Froquiz canvas, connect the data flow, and see which decisions the scenario-specific review finds missing. The full exercise and review unlock with Premium.
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