Serverless event-driven backbone
An event bridge routing to two styles side by side — choreographed functions reacting to events, and a step-function orchestrator owning a flow — with async request-reply and DLQ routing.
What this design does
Serverless architectures die by spaghetti when every function invokes the next. This backbone shows the two disciplined alternatives on one canvas: choreography (functions react to routed events) for loose coupling, and orchestration (a state machine owns the sequence) for flows you must reason about. The client never waits — 202 plus a status endpoint is the async contract.
The patterns it composes
- Event bridge / content-based router — producers emit once; routing rules decide who cares
- Choreography vs orchestration — react-to-events for autonomy, state machine for auditable flows
- Async request-reply — 202 Accepted + status endpoint instead of held connections
- Cold-start mitigation — provisioned concurrency keeps the hot path warm
- DLQ + destination routing — failed invocations route to dead letters, not silence
Import it, attach your own numbers, and verify the design against failures — or read the engineering notes.