{
  "name": "welcome-onboarding-email",
  "to": [
    {
      "subscriberId": "subscriber_123",
      "email": "jane@example.com"
    }
  ],
  "payload": {
    "firstName": "Jane",
    "appName": "Acme",
    "verificationUrl": "https://app.acme.com/verify?token=abc"
  },
  "transactionId": "tx_8f7e6d5c-4321-4abc-9def-1234567890ab",
  "tenant": "tenant_acme"
}