curl --request POST \
  --url https://api.sandbox.monite.com/v1/payable_purchase_orders/{purchase_order_id}/preview \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --header 'x-monite-entity-id: <x-monite-entity-id>' \
  --header 'x-monite-version: <x-monite-version>' \
  --data '
{
  "body_text": "<string>",
  "subject_text": "<string>"
}
'

{
  "body_preview": "<string>",
  "subject_preview": "<string>"
}