Hammerdown turns any product in your catalog into a timed auction, without moving your store anywhere else. Shoppers bid from the product page and watch every bid land in real time. Buyers can set a private maximum and let the app bid on their behalf. A bid in the closing seconds pushes the end time out, so an auction ends when the bidding does. When it closes, the winner is invoiced automatically at the price they won, and the product cannot be bought at its catalog price by anyone else.

• Real-time bidding on product pages, plus a live auction grid page
• Popcorn bidding, proxy bidding, reserve price, and buy it now
• Checkout enforcement: only the winner can purchase the auctioned item
• Automatic invoicing, with runner-up reassignment when a winner never pays
• Buyer's premium, invite-only auctions, bulk CSV creation, and a bidding API