curl --request PUT \
  --url 'https://prod-api.stateset.cloud.stateset.app/api/v1/checkout/{session_id}/shipping-method' \
  --header 'Authorization: Bearer YOUR_API_KEY' \
  --header 'Content-Type: application/json' \
  --data '{
  "method": "Standard"
}'

{
  "data": {
    "amount": "49.00",
    "estimated_days": 1,
    "method": "Standard"
  },
  "errors": [
    "string"
  ],
  "message": "Two-person tent, green — replacement for damaged pole set.",
  "meta": {
    "request_id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
    "timestamp": "2026-08-31T14:22:05Z"
  },
  "success": true
}