curl --request POST \
  --url https://reelmirror.com/api/v1/publishing/accounts/slots \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "slots": 1,
  "returnUrl": "<string>"
}
'

{
  "data": {
    "purchased": 123,
    "subscriptionId": "<string>",
    "checkoutUrl": "<string>"
  }
}