I built a reverse proxy load balancer in Go (with health checks + failover)

I wanted to understand how real load balancers work under the hood, so I built one in Go using only the standard library. A minimal implementation that still incorporates essential building blocks of production-style load balancers: Reverse proxy using httputil.ReverseProxy Atomic round-robin load balancing (no mutex) Active health checks (runs every 10s, concurrent probing) Automatic failover + retry on backend failure Structured request logging Skips unhealthy backends dynamically Architecture: Client → Load Balancer (:8080) → Backend servers (:9001, :9002, :9003) How it works: Each request is forwarded through a reverse proxy A global atomic counter distributes traffic (round-robin) Health checker continuously probes /health on each backend If a backend fails → it’s marked down and skipped Proxy retries request on the next available backend One thing I found interesting: Go’s httputil.ReverseProxy gives you hooks like ErrorHandler, which makes it possible to implement retry/failover