generated: '2026-07-18'
method: searched
type: Webhooks
source: https://docs.aciworldwide.com/tutorials/integration-guide/webhooks
description: >-
  ACI OPPWA delivers server-to-server webhook notifications instead of requiring
  polling. A webhook is configured once (endpoint + encryption parameters) and
  the platform pushes events when relevant state changes occur. No AsyncAPI
  document is published by ACI, so this captures the webhook catalog as the event
  surface (type: Webhooks).
transport: https-post
security:
  payload_encryption: AES-256-GCM
  detail: >-
    Payloads are delivered encrypted. The initialization vector and
    authentication tag are supplied in request headers; the body is decrypted
    with the configured secret key and the auth tag validated for integrity
    before parsing the JSON event.
event_categories:
- name: payment
  description: Payment/transaction state changes (authorization, capture, refund, reversal, decline).
- name: registration-token
  description: Tokenization / stored payment credential (registration) updates.
- name: scheduled-payment
  description: Recurring / scheduled payment execution events.
- name: risk-decision
  description: Fraud/risk scoring decisions and blacklist actions.
- name: transaction-state
  description: General transaction state-change notifications, including confirmation of pending (non-instant) payments.
notes: >-
  Especially important for pending outcomes (result codes 000.200.x /
  800.400.5x), where the final result arrives asynchronously via webhook rather
  than in the original API response.