The Publisher/Subscriber pattern decouples event producers from event consumers. Producers emit events without knowing who receives them; subscribers independently react.
Azure Event Grid is purpose-built for event routing in Azure, making it a common backbone for integration and automation scenarios.
Use Pub/Sub when:
- multiple downstream systems need to react to the same business event,
- you want to add/remove subscribers without changing the producer,
- you want near-real-time integration.
Avoid it when:
- you need strict point-to-point command processing (a queue may be better).
flowchart LR
P["Publisher<br/>(App/Service)"] --> EG[Event Grid\nTopic]
EG --> S1["Subscriber 1<br/>(Logic App)"]
EG --> S2["Subscriber 2<br/>(Azure Function)"]
EG --> S3["Subscriber 3<br/>(Webhook/API)"]
- Event contract versioning: evolve event schemas safely.
- Idempotency: subscribers should tolerate duplicate deliveries.
- Error handling: define what happens when a subscriber can’t process an event.
- Event vs command: publish facts (“OrderCreated”), not instructions (“CreateOrder”).
- Publisher/Subscriber pattern: https://learn.microsoft.com/en-us/azure/architecture/patterns/publisher-subscriber
- Cloud design patterns catalog: https://learn.microsoft.com/en-us/azure/architecture/patterns/
- Azure Event Grid documentation: https://learn.microsoft.com/en-us/azure/event-grid/