curl --request PATCH \
  --url https://{defaultHost}/v1/shipments/{id}/purchase \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "shipment": {
    "rate_id": "rate_1",
    "label_file_type": "PDF"
  }
}
'

{
  "id": "df8506a2-83b5-49a6-bc95-4be4b17a920e",
  "object": "shipment",
  "status": "purchased",
  "live_mode": true,
  "label_url": "https://deliver.goshippo.com/1e3adda1934443079737edb336067106.pdf?Expires=1806494587&Signature=YcAo0uG7lvxdwCmD8KPOui7O~u7KGPKWQszBtrLcdfQg5hdRZlfabsM4zSa69zRVgpEH8Omon0ktgRETyPPoIP9WOyW4CvKa7tEKyoOMi04YQ7JLCNZJXybHoJ9Z31gYqfd5RYfn1SoFTaFUDjQ17Id9RMTGG-JICM7a8fbsKFBoaGEE6zme~POyX~KX2rhlv2XiQFfmXhoJn1tF1yeh0gTJ4Ayefno4u34AeiS2XipX1anBqYyrtsxIXa7gG8NC-QufLNSgBUMcnkDLT04aa8-XXvI7IsVAkml1QqzAHq2Ur-2HVYaxYhA1V3VUjkwv8E6LwkyS~23jEysytNbdNw__&Key-Pair-Id=APKAJRICFXQ2S4YUQRSQ",
  "label_file_type": "PDF",
  "tracking_number": "9234690396055702568186",
  "tracking_url": "https://tools.usps.com/go/TrackConfirmAction_input?origTrackNum=9234690396055702568186",
  "tracking_status": null,
  "eta": null,
  "weight": "2.0",
  "weight_unit": "lb",
  "shipping_date": 1775174400,
  "carrier": "USPS",
  "dimensions": {
    "length": 10,
    "width": 8,
    "height": 5,
    "unit": "in"
  },
  "rates": [
    {
      "id": "rate_1",
      "amount": 550,
      "currency": "usd",
      "provider": "USPS",
      "service_name": "Priority",
      "estimated_days": 3,
      "tags": [
        "bestvalue"
      ],
      "duration_terms": null,
      "provider_logo_url": "https://example.com/usps.png"
    }
  ],
  "selected_rate": {
    "id": "rate_1",
    "amount": 550,
    "currency": "usd",
    "provider": "USPS",
    "service_name": "Priority",
    "estimated_days": 3,
    "tags": [
      "bestvalue"
    ],
    "duration_terms": null,
    "provider_logo_url": "https://example.com/usps.png"
  },
  "fulfillment": "14999bec-6631-46b5-adc6-619aa671bbb6",
  "shipping_provider": "718d5e4e-2ab4-4809-9466-bb8f1dcea3d8",
  "from_contact": "be23ea53-2aec-472f-ba57-b2681f36aadb",
  "to_contact": "0406b899-ce85-4a72-85a6-9e125e308920",
  "parcel_template": null,
  "created_at": 1775219013,
  "updated_at": 1775219013
}