End-to-end SaaS request flow: web and mobile clients hit a CDN/edge network and load balancer that route into a three-service API tier (auth, billing, onboarding) owned by the platform team, which reads and writes a shared Postgres database and Redis cache owned by the data platform team, while the onboarding service enqueues longer-running work onto a message queue consumed by an asynchronous worker pool that writes results back to Postgres.