Load Balancer Simulator — Interactive System Design Lab
Simulate traffic across multiple servers using different load balancing algorithms. Watch how request distribution changes under round-robin, least-connections, and random strategies. Take individual servers offline to see how the balancer routes around failures — and understand when each approach is the right choice in a real system design interview.
Compare round-robin, least-connections, and random routing — and kill servers to test fault tolerance.
This free interactive simulation runs directly in your browser — no account needed. Adjust the parameters and watch how the system responds in real time.
Concepts covered
- load balancer
- round robin
- least connections
- traffic distribution
- horizontal scaling
- fault tolerance
- server failover
- health check
Read the guide
- Load Balancing — The unsung hero of scalability. It protects your servers from crushing load and gives you the freedom to fail without downtime.