How does Platform Event work in Salesforce?
Platform Events enable loosely coupled, event-driven architectures within and beyond Salesforce. A publisher (whether Apex, Flow, an API client, or a Process Builder) publishes an event to a named channel. Subscribers (Apex triggers, Flow, Lightning components, or external systems via CometD/gRPC) receive the event in near real-time. Events are defined as custom sObjects with the __e suffix and can carry custom fields that represent the event payload.
Platform Events support two delivery modes: standard delivery (at-most-once, no replay) and high-volume delivery (durable, with 72-hour replay and ReplayId tracking for reliable consumption). They are transactional in before-commit contexts but can also be published using EventBus.publish() with immediate delivery outside the transaction boundary. Common use cases include triggering downstream processes after complex operations, integrating with external middleware (MuleSoft, Kafka), broadcasting changes to multiple subscribers, and implementing error logging frameworks. Clientell AI uses platform events to track org changes in real-time.