TO PREVENT YOUR PAID USERS FROM LOSING AUCTIONS DUE TO EXPIRED EBAY AUTH TOKEN -- YOU NEED TO HAVE A NOTIFICATION SYSTEM IN PLACE TO ALERT THEM OF SUCH -- BEFORE BIDS ARE PLACED!
Snipe Log for Item 335450781786
Time Host Event
2 2024-06-26 04:36:00 Bid added for 33.33. Current price: 5.
2 2024-07-02 12:24:00 Initializing snipe. Item ends at 2024-07-02 12:26:22 PST.
2 2024-07-02 12:24:00 Sleeping for 139 seconds.
2 2024-07-02 12:26:19 Placing bid for 33.33.
2 2024-07-02 12:26:19 Snipe completed. eBay processed snipe in 0.207 sec.
2 2024-07-02 12:26:23 Auth token hard expired: Our authorization with eBay to bid on your behalf has "hard expired," accor...
2 2024-07-02 12:26:23 Snipe execution completed.

Hello,
Thanks for your suggestion. Yes, we do already check the eBay token every 8 hours before the auction is placed. We also check it each time you come to the site. We also sent an email to you in the event we are able to catch it.
If you have any suggestions on how we could improve, I would surely like to know so that we can implement the feature.
I hope this has been explained to your satisfaction. If not, we welcome further feedback.

Your algorithm could be adjusted to check auth token, say, 2 hours before an auction closing. That would be enough time to alert buyer to fix the issue.
I have a very sensitive security system that sends me texts and emails every time even if a shadow moves or a bird comes in range. I am always checking my email unless I have intentionally set it aside. If a 2-hour heads-up had been sent, I very quickly would have remedied the issue before auction close. This email of course never came from Bidslammer in time. I only discovered the issue after auction end — and I missed out on an ultra rare item you only see every 2 to 3 years on eBay. Oh well.

This is not possible. eBay limits the number of calls we can make. It is forbidden to continually poll your account in this fashion.
If we were to do this we'd have to do it for every snipe for every customer, which would be over a half million calls a day.