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Message bus and event log

The bus and the event log are not the same thing.

Use the bus for live coordination​

Routes:

  • GET /v1/sessions/{sessionId}/bus
  • POST /v1/sessions/{sessionId}/bus:publish

Use the bus when you need:

  • live progress messages
  • tool-to-tool coordination
  • short-latency updates
  • replay of recent retained messages

The subscribe route is long-lived and streaming.

Use the event log for durable history​

Route:

  • GET /v1/sessions/{sessionId}/events

Use the event log when you need:

  • history
  • support investigation
  • audit-style review
  • paginated replay of past state changes

Bus versus events​

Choose the bus when:

  • the consumer is listening now
  • you care about live workflow state
  • you want topic-based filtering

Choose events when:

  • the consumer is reconstructing history
  • you want a durable list of past changes
  • time windows and pagination matter

Bus versus cache​

Use:

  • bus for live messages
  • cache for keyed durable workflow data

Do not use one as a substitute for the other.