Payment Notification Event

Overview

Payment Notification Event is a machine-readable event emitted when a payment or related object changes state or when an operational condition requires another system to react. The producer records the change, creates an event with identifiers and versioned payload, and delivers it through a webhook, stream, queue, or internal event bus. The relationship with Payment State Version matters because one payment can appear as multiple requests, events, provider references, and ledger entries.

Operationally, the producer records the change, creates an event with identifiers and versioned payload, and delivers it through a webhook, stream, queue, or internal event bus. The event reports that a change was observed; it is not automatically the authoritative payment record or proof that the consumer applied the change. The record should retain event identifier, payment identifier, event type, object version, occurrence and delivery times, producer, signature, attempts, acknowledgements, and consumer result.

Payment Notification Event should remain distinct from Payment Message, Payment State Version, and Payment State Replay, because each can represent a different stage, record, control, or financial outcome. Governance for Payment Notification Event needs a named owner, review cadence, approved changes, and rollback.

Important risks include out-of-order delivery, duplicates, missing events, stale payloads, forged callbacks, consumer downtime, schema changes, and irreversible actions triggered too early. Useful measures include delivery success, retry rate, consumer lag, duplicate rate, ordering conflicts, signature failures, and event-to-state consistency. Tests should cover normal traffic, edge cases, partial failure, and downstream financial evidence.

Controls should preserve original payloads, correlation and causation identifiers, delivery attempts, validation results, consumer acknowledgements, and any replay or dead-letter action.