NotificationSubscriptionRequest

{
    "subscription_id": "20251022-0949-42c7-947d-67f32a1ecf45",
    "channel_type": "callback",
    "notification_types": [
        "transaction_approved"
    ],
    "targets": [
        "https://example.com/callback-endpoint",
        "https://another-endpoint.com/callback"
    ]
}