curl --request POST \
  --url https://api.withorb.com/v1/customers/external_customer_id/{external_customer_id}/portal_sessions \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "expires_in_minutes": 60
}
'

{
  "id": "<string>",
  "customer_id": "<string>",
  "created_at": "2023-11-07T05:31:56Z",
  "expires_at": "2023-11-07T05:31:56Z",
  "url": "<string>"
}