[beastcoast]

>1000 services, each with many APIs :)

Amazon's warehouses have incredible domain complexity which drives the complexity of the software architecture. It's also one of the oldest parts of the company with a direct lineage going back 20+ years. (for example, our inventory databases still have the same schema and are still using a RDBMS, albeit RDS Postgres instead of Oracle).

About five years ago we started rearchitecting to a centralized orchestration service which is being used to abstract this complexity from process teams. This is to avoid projects where 20+ service teams must be engaged just to launch a new solution.