Louped (Formerly idonowidont) is an e-commerce website that markets preowned owned jewelry, primarily diamond engagement rings, as well as other items such as loose diamonds, fine and vintage jewelry, men's and women's pre-owned watches, and men's and women's pre-owned wedding bands through fixed-price and auction sales.

Louped (Formerly idonowidont) was founded by Joshua Opperman and his sister Mara in 2007, as a peer-to-peer platform for selling expensive engagement and wedding rings that are no longer wanted. Opperman says he had the idea after returning home one day to find that his fiancée of three months and all of her belongings, aside from the ring, were gone; when he tried to return the ring to the retailer, he received a buyback estimate that was about a third of the purchase price. Jewelry on louped is typically priced higher than retailer buyback offers but up to 50% below appraisal value.