curl --request POST \
  --url https://api-message.nativehub.live/api/v1/templates/{id}/preview \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "variables": {
    "name": "Alice",
    "otp": "123456",
    "validity": "5"
  }
}
'

{
  "preview": "Dear Alice, your OTP is 123456. Valid for 5 minutes."
}