Messaging Pub/Sub

Pub/Sub

Publish events once; multiple subscribers consume independently. Great for fanout and integrations.

When to use

  • One event triggers multiple side effects
  • You want to add consumers without changing producers
  • Integrations with email/SMS/webhooks/queues

Trade-offs

  • Harder to reason about end-to-end flows
  • Delivery semantics vary by system and subscription type
  • You still need idempotent handlers

References