Designed & built a full-stack URL shortener in Go using Chi, PostgreSQL, and Redis (cache-aside pattern), with server-side rendered homepage via Go templates. Load-tested with k6 at 100 concurrent users (10k requests): 0% error rate, ~260ms median / ~339ms p95 latency, 362 req/s on a Render free-tier instance (0.1 vCPU, 512 MB RAM).