generated: '2026-08-26'
method: searched
source: >-
  https://developers.momo.vn/v3/docs/payment/api/result-handling/notification/,
  https://developers.momo.vn/v3/docs/business-page/user-activities/user-activities-list/,
  https://developers.momo.vn/v3/docs/business-page/user-activities/retry-mechanism/,
  https://developers.momo.vn/v3/docs/business-page/user-activities/implement-condition/
note: >-
  MoMo publishes NO AsyncAPI document, no event catalog in a machine-readable
  format, and no streaming surface — searched developers.momo.vn (212-URL
  sitemap), github.com/momo-wallet, and probed /asyncapi.json,
  /.well-known/* on every host. What it does publish is two real, documented
  server-to-server callback surfaces, captured here as a webhook catalog. This
  is a Webhooks artifact, not an AsyncAPI one, and it is typed that way in
  apis.yml on purpose.
surfaces:
- id: aio-ipn
  name: AIO v2 Instant Payment Notification (IPN)
  api: momo:aio-payment-gateway
  direction: MoMo -> merchant
  subscription: >-
    Per-request, not per-account: the merchant supplies an `ipnUrl` in the
    create/pay request body. There is no webhook registration console and no
    endpoint management API.
  transport: HTTPS POST
  content_type: application/json
  expected_response: HTTP 204 No Content, within 15 seconds
  signature:
    field: signature
    algorithm: HMAC-SHA256
    verification_required: true
    note: >-
      MoMo instructs merchants to validate the IPN signature AND to cross-check
      partnerCode, orderId and amount against their own database before acting.
  url_constraints: >-
    The ipnUrl must be a path only — no query parameters, no special characters,
    no unicode, no spaces.
  redirect_companion:
    method: GET
    field: redirectUrl
    note: >-
      A browser redirect with query parameters is delivered alongside IPN. It is
      a user-agent event, not a server event, and MoMo warns it can be lost when
      the user closes the browser — which is the stated reason IPN exists.
  payload_fields:
  - partnerCode
  - orderId
  - requestId
  - amount
  - orderInfo
  - orderType
  - transId
  - resultCode
  - message
  - payType
  - responseTime
  - extraData
  - signature
  event_semantics:
    resultCode_0: Transaction succeeded
    resultCode_9000: Transaction authorized successfully (awaiting capture or cancel)
    resultCode_other: Transaction failed — see errors/momo-error-codes.yml
  caveat: >-
    MoMo states explicitly that it will NOT use the merchant's IPN response to
    refund a transaction, for cash-flow and balance-reconciliation reasons. A
    non-2xx IPN response does not reverse anything.
  retry_policy: not-published
  docs: https://developers.momo.vn/v3/docs/payment/api/result-handling/notification/
- id: business-page-user-activities
  name: Business Page user-activity events
  api: momo:business-page-openapi
  direction: MoMo -> partner
  subscription: A partner-registered callback URL, registered with MoMo (not self-serve).
  transport: HTTPS
  event_count: 7
  events:
  - code: VIEW
    source: Business Page
    description: A user opened the page.
  - code: CLICK_ON_CTA
    source: Business Page
    description: A user tapped one of the page's main call-to-action buttons.
  - code: SUBSCRIBE
    source: Business Page
    description: A user followed the page.
  - code: UNSUBSCRIBE
    source: Business Page
    description: A user unfollowed the page.
  - code: REVIEW_POST
    source: Ratings & reviews
    description: A user posted a rating or review.
  - code: UPDATE_POST
    source: Posts
    description: A post's status changed.
  - code: COMMENT_POST
    source: Posts
    description: A user interacted with a post — like, comment, share, or reply to another user's comment.
  retry_policy:
    published: true
    schedule: [30 seconds, 5 minutes, 15 minutes]
    retry_counter: >-
      Redelivered events carry the same content plus a count of how many times
      the event has been retried.
    failure_terminal: >-
      If the partner's receiver is still not responding after the retry schedule
      is exhausted, MoMo stops sending events and marks the subscription
      inactive — the partner must reactivate it.
    docs: https://developers.momo.vn/v3/docs/business-page/user-activities/retry-mechanism/
not_published:
  asyncapi_spec: false
  event_schemas: >-
    No JSON Schema or machine-readable payload definition for either surface —
    payload fields are documented in HTML tables only.
  streaming: >-
    No WebSocket, SSE, Kafka, webhook-replay or event-history API on any MoMo
    surface.
  webhook_management_api: >-
    No API to create, list, rotate or delete callback endpoints. AIO endpoints
    are per-request; Business Page endpoints are registered with MoMo out of band.
  signing_key_rotation: >-
    The IPN signature reuses the merchant's secretKey; no separate webhook signing
    secret and no rotation procedure is documented.