It may sound like the name of a magician for hire, but it isn't.
Cassini is the name of eBay’s search engine.
It's important to know how Cassini works because for eBay listings, search is everything.
Aron Hsiao at The Balance Small Business says,
"Because eBay's marketplace is highly search-oriented, sellers who achieve good search rankings— mom database that is, appearing on the first or second page of results—sell products."
Sellers who don't rank well in search struggle to survive."
Cassini tracks a number of metrics to determine the position of your listing.