Build a Layer-7 Load Balancer

You build a layer-7 load balancer: an HTTP reverse proxy that accepts client connections, forwards requests to a configurable pool of backend servers, returns their responses, and continuously health-checks backends so traffic only goes to healthy ones. You make the balancing strategy pluggable, implementing round-robin and least-connections, and handle concurrency so many clients are served at once. It is worth building because load balancing sits at the heart of every production system, and implementing one teaches the proxy patterns, connection handling, and failure detection that infrastructure roles live and breathe. It is resume-defining because it demonstrates you understand high-availability traffic management from the inside rather than as a managed cloud checkbox, including how health checks, draining, and algorithm choice affect real reliability.