HAProxy is an open-source solution for load balancing and reverse proxying that provides high availability and can handle both TCP and HTTP requests. It consistently performs well in benchmarks against other popular reverse proxies, making it a fundamental element in the architecture of many high-profile websites. Monitoring HAProxy's key metrics is crucial to ensure proper performance and operation, as poor load balancer performance can increase latency across the entire stack. Frontend metrics provide information about client interactions with the load balancer, while backend metrics measure communication between HAProxy and backend servers handling client requests. Health metrics expose information about the health of each front and backend server. Monitoring these metrics can help identify potential hotspots, diagnose issues, and optimize HAProxy configuration for better performance and availability.