Launch day: 15,000 rps, and the product cannot go down or crawl — 99.99% availability, p99 ≤ 110 ms, critical durability, under $2,200/mo. You start with only a bare single-AZ fleet and a database.
Build the rest from the palette and tune everything: an autoscaling Graviton origin across three AZs, a CDN for edge load, an ElastiCache tier, and a Multi-AZ database with a read replica so the data tier survives an AZ loss too. Watch the budget — this is the full boss fight.