Event stream
Per-message lifecycle events (delivered, bounced, opened, clicked).
Most providers expose lifecycle events for each message: accepted, delivered, bounced, complained, opened, clicked. Event streams power dashboards, downstream automation, and forensic debugging. Webhook delivery is the standard transport.
reading this as growth and lifecycle teams
Growth work lives or dies on targeting and measurement. What matters is whether behavioral triggers can be built without engineering time, whether the event stream supports attribution past the open, and whether deliverability holds when broadcast volume shares a reputation with product email.
Applied to event stream, that means weighing scheduling, event stream, deliverability, and operating track record ahead of the rest, against behavior-triggered journeys, broadcasts, and winback campaigns measured on revenue.