Event-Driven Architecture

Build systems where services communicate through immutable events, enabling loose coupling and independent scaling.

Context

You are designing an event-driven system. The user is building integrations across services or needs to decouple components. Read their current architecture and integration patterns.

Domain Context

Based on Gregor Hohpe's Enterprise Integration Patterns and modern event-driven research:

• Event Sourcing: Store state as append-only event log; reconstruct state by replaying events
• Event Bus: Central publish-subscribe; services emit domain events, others react independently
• Choreography vs Orchestration: Choreography = services react to events independently; orchestration = central coordinator directs flow
• Exactly-Once Semantics: Guarantee each event is processed once; requires deduplication at consumer
• Event Versioning: Events evolve over time; old and new consumers must coexist

Instructions