# Message Bus

> Enterprise-wide messaging backbone — every app connects to the bus and communicates through it.

- **Category**: Integration
- **Subcategory**: System Management
- **Canonical URL**: https://designpattern.fyi/patterns/message_bus/

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## Description
Clean, reusable architecture pattern.


## Use Cases
Insurance company message bus — 30 applications (CRM, underwriting, claims, billing, partner portals) all connect to a central Kafka-based bus. Policy events flow from underwriting to billing and partner systems. Claims flow to underwriting and CRM. All via the bus — no point-to-point integrations.





## Trade-offs


### Advantages

- Single connectivity model for all enterprise applications

- Eliminates point-to-point integration spaghetti

- Standardized protocols and formats enterprise-wide

- New applications connect once and gain access to all bus participants




### Considerations & Drawbacks

- Bus is a critical central dependency — failure impacts all connected applications

- Governance and standards enforcement require organizational discipline

- Performance bottleneck at high message volumes if bus is not properly scaled

- Initial setup and migration of all applications is a major program







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**Reference**: [Original Source](https://www.enterpriseintegrationpatterns.com/patterns/messaging/MessageBus.html)