Soft close (or “auto-extend”) is an auction-close mechanism where, if a bid is placed within the final minute (or other defined window) before the lot’s scheduled close time, the close time extends automatically by the same window. The lot only closes when no new bids arrive for the full extension period.
Soft close is the standard countermeasure against sniping. By extending the close every time a late bid arrives, it gives previous high bidders fair opportunity to respond. Most online auctions use 1–3 minute soft-close windows. The trade-off is unpredictable close times — bidders watching multiple lots have to be patient as one lot’s close cascades into others.
Soft close emulates the behavior of a live auctioneer asking “going once, going twice” before dropping the hammer — the lot doesn’t close until bidders have stopped bidding. Different platforms use different window lengths: eBay-era hard close (no extension) is increasingly rare; Bring A Trailer uses 2-minute extensions; specialty livestock and equipment platforms sometimes use 30-second windows for faster close cycles. The right window length depends on the category — collectibles benefit from longer windows because bidders need time to think; commodity inventory benefits from shorter windows because pace matters more.