const options = {
  method: 'PATCH',
  headers: {
    'x-spree-api-key': '<api-key>',
    Authorization: 'Bearer <token>',
    'Content-Type': 'application/json'
  },
  body: JSON.stringify({
    tracking_number: '<string>',
    carrier: '<string>',
    service: '<string>',
    tracking_url: '<string>'
  })
};

fetch('http://{defaultHost}/api/v3/admin/orders/{order_id}/fulfillments/{fulfillment_id}/deliveries/{id}', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

curl --request PATCH \
  --url http://{defaultHost}/api/v3/admin/orders/{order_id}/fulfillments/{fulfillment_id}/deliveries/{id} \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --header 'x-spree-api-key: <api-key>' \
  --data '
{
  "tracking_number": "<string>",
  "carrier": "<string>",
  "service": "<string>",
  "tracking_url": "<string>"
}
'

{
  "id": "dlv_UkLWZg9DAJ",
  "tracking_number": "CORRECTED-1",
  "carrier": null,
  "carrier_name": null,
  "service": null,
  "status": "pending",
  "tracking_url": null,
  "estimated_delivery_at": null,
  "delivered_at": null,
  "details": null,
  "created_at": "2026-01-15T12:00:00.000Z",
  "updated_at": "2026-01-15T12:00:00.000Z",
  "shipping_label_id": null
}