curl --request POST \
  --url https://api.headlesscommerce.io/v1/admin/customers \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "email": "<string>",
  "first_name": "<string>",
  "last_name": "<string>",
  "phone": "<string>",
  "external_id": "<string>",
  "tags": [
    "<string>"
  ],
  "metadata": {}
}
'

{
  "id": "<string>",
  "email": "<string>",
  "first_name": "<string>",
  "last_name": "<string>",
  "phone": "<string>",
  "external_id": "<string>",
  "total_orders": 123,
  "total_spent": {
    "amount": 123,
    "currency": "<string>"
  },
  "tags": [
    "<string>"
  ],
  "addresses": [
    {
      "name": "<string>",
      "company": "<string>",
      "line1": "<string>",
      "line2": "<string>",
      "city": "<string>",
      "state": "<string>",
      "postal_code": "<string>",
      "country": "<string>",
      "phone": "<string>"
    }
  ],
  "metadata": {},
  "created_at": "2023-11-07T05:31:56Z"
}