Load Balancing Explained: Algorithms, Layers, and the Single Point of Failure Risk

Load balancers sit between clients and backend servers, distributing incoming traffic so no single server is overwhelmed — but the choice of algorithm matters significantly. Common strategies include round robin, least connections, and IP hash, each suited to different traffic patterns and statefulness requirements. Load balancers also operate at either Layer 4, routing by IP and port for speed, or Layer 7, inspecting request content for smarter but costlier decisions. Built-in health checks allow load balancers to detect and stop routing traffic to failed servers, effectively doubling as a monitoring layer. However, a single load balancer itself becomes a critical point of failure, which is why production systems typically run multiple load balancer instances behind DNS round robin for redundancy.