Webhook Events

WhatsApp contact identity changed event

Fired when a WhatsApp user changes phone number or Meta regenerates their business-scoped user id (BSUID). Carries the previous and current identifiers so you can re-key records stored against the old phone number or BSUID. Delivery is at-least-once; dedupe on the event id.

postWebhookwhatsapp.contact.identity_changed

Payload

idstring required

Stable webhook event ID: the dedupe key, also sent as the X-Zernio-Event-Id header and identical on every retry and redelivery. It identifies the event only, never an account or other resource.

event'whatsapp.contact.identity_changed' required

reason'user_changed_number' | 'user_changed_user_id' | 'user_identity_changed' | 'user_id_update' required

Which Meta signal reported the change. user_changed_number: new phone number. user_changed_user_id and user_id_update: new BSUID.

contactIdstring nullable required

Zernio contact id matched on the new identity, null when none exists yet.

conversationIdstring nullable required

Zernio inbox conversation that was re-keyed, null when there was none.

changedAtstring date-time required

When Meta reported the change.

timestampstring date-time required

UTC time at which Zernio generated this event (set once when the event payload is built, before delivery is queued). Retries and redeliveries keep the original value, so it reflects the event, not the delivery attempt.

Example payload

{
  "id": "7f1c2d4e-0000-4000-8000-000000000001",
  "event": "whatsapp.contact.identity_changed",
  "account": {
    "accountId": "6a0000000000000000000001",
    "profileId": "6a0000000000000000000002",
    "platform": "whatsapp",
    "username": "+15550001111",
    "displayName": "Acme"
  },
  "reason": "user_changed_number",
  "previous": {
    "phoneNumber": "18325355831",
    "businessScopedUserId": "US.13491208655302741918",
    "parentBusinessScopedUserId": null,
    "whatsappUsername": null
  },
  "current": {
    "phoneNumber": "15129984441",
    "businessScopedUserId": "US.13491208655302741918",
    "parentBusinessScopedUserId": null,
    "whatsappUsername": null
  },
  "contactId": "6a0000000000000000000003",
  "conversationId": "6a0000000000000000000004",
  "changedAt": "2026-09-30T12:00:00.000Z",
  "timestamp": "2026-09-30T12:00:01.000Z"
}

Response

Webhook received successfully

Changes

Webhooks have no change history: a webhook is keyed by its event name rather than a path and method, so no recorded change can name it.