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Load Balancer Challenge

Route simulated traffic across backend servers using round robin, weighted round robin, least connections, and random strategies.

Concept
Load balancing strategies
Difficulty
Intermediate
Play time
6-10 minutes
Path
Production Reliability

Interactive scenario

Playable game area: Make the next backend decision

Use the controls below. Feedback appears immediately and final scores stay in this browser.

Concept notes

Why this decision matters

Load Balancer Challenge is focused practice for Load balancing strategies. It explains why each answer is safe, risky, or production-ready.

Scaling a backend is not only adding servers. Traffic has to be distributed in a way that respects capacity, health, and active work.

Learning objectives

  • Compare routing strategies under changing server capacity.
  • Understand overload, latency, and health-aware routing.
  • Connect horizontal scaling to practical traffic distribution.

How to play

  1. Read the scenario about load balancing and its evidence about capacity, connections, or health.
  2. Choose one strategy that best addresses the risk to server capacity described.
  3. Select Submit decision, read the explanation, then choose Next challenge or Finish run.
  4. The gauges illustrate the scenario; they are not measured latency, throughput, or overload results.

Scoring

  • Your score ranges from 0 to 1000 and reflects the quality of your decisions.
  • Consistently strong decisions at harder difficulty levels earn an extra bonus.
  • Completing all eight decisions adds a completion bonus.
  • Response time does not affect your score. Take time to read the evidence and explanations.

Backend concept notes

Load balancers distribute traffic across multiple backend instances. The best strategy depends on request cost, server capacity, health, and whether user sessions need stickiness.

Round robin is simple, weighted routing handles different capacity, and least connections reacts to uneven active work.

Common mistakes

  • Treating all servers as equal when they have different capacity.
  • Ignoring server health during traffic spikes.
  • Using sticky sessions without considering uneven load.

Review misses from this game

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Concept
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FAQ

Short answers for how this game fits backend interview and study practice.

Why is random routing included?

Random routing is simple and can work surprisingly well at scale, but it can be unstable in small simulations or uneven server pools.

What are sticky sessions?

Sticky sessions route a user back to the same backend instance, which can help session state but may create uneven load.

Leaderboard

Top 10 scores for the current ruleset. No account required.

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