Payload

All webhook payloads follow a consistent top-level structure with event-specific data nested within the data object.

subscriptionIdstring

The subscription ID.

customerIdstring

The customer ID. Returns your externalId if you provided one when creating the customer, otherwise returns the Commet publicId.

previousPlanWebhookPlanRef

The previous plan (id and name).

currentPlanWebhookPlanRef

The new plan (id and name).

billingIntervalstring | null

The billing interval (monthly, yearly).

creditnumber

Prorated credit in cents from the previous plan.

chargenumber

Prorated charge in cents for the new plan.

totalChargednumber

Total amount charged in cents.

{
  "event": "subscription.plan_changed",
  "timestamp": "2026-06-23T14:30:00.000Z",
  "organizationId": "8f14e45f-ceea-4e7a-9c3d-1c2b3a4d5e6f",
  "mode": "live",
  "apiVersion": "2026-07-31",
  "data": {
    "subscriptionId": "sub_1a2b3c4d",
    "customerId": "user_123",
    "previousPlan": {
      "id": "pln_starter",
      "name": "Starter"
    },
    "currentPlan": {
      "id": "pln_pro",
      "name": "Pro"
    },
    "billingInterval": "monthly",
    "credit": 1500,
    "charge": 4900,
    "totalCharged": 3400
  }
}