Most discord bot listings use webhooks as a method of telling you who upvoted your bot, to recieve these webhooks, you need to have some kind of web server that's able to process them, if you don't have a dedicated web server that you can expose to the internet, you can read how to do this using other services here.
This method of recieving webhooks is generally easier to manage since you are recieving the data directly, however you need to remember that this is a web server and it will require the same security as if you were running any other site / API. The code below by default returns 403 errors if the token provided in the Authorization header is not correct or if header does not exist, you can use this in a firewall to determine if someone is trying to access it. (This returns a 403 for this event only, and does not stop people brute forcing for pages, or attempting a DoS attack)
There will be some variables for you to modify in the