System Design & Architecture

System design separates mid-level from staff engineers, commanding 40-200k salary premiums. Juniors start with single-service architecture basics (6-12 months), midlevels master distributed systems (2-3 years), seniors architect global-scale infrastructure. Core tools include databases, load balancers, message queues, caching layers. Certified architects earn 180-280k+ (USA). Time investment 18-36 months to competence.