curl --request GET \
  --url https://api.{your-broker}.slate-labs.com/webhooks/{webhook_id}/deliveries/stats

{
  "total_deliveries": 123,
  "successful": 123,
  "failed": 123,
  "success_rate": 123,
  "avg_duration_ms": 123,
  "total_delivered_today": 123,
  "last_delivery_at": "2023-11-07T05:31:56Z"
}