TL;DR — eBay Auction System

Design an online auction system similar to eBay where sellers list items for time-based auctions and buyers place competitive bids. The system must handle real-time bidding, enforce auction end times precisely, manage bid concurrency to ensure the highest bidder always wins, and implement anti-sniping mechanisms to prevent last-second bid manipulation. Key features: Sellers create auctions with starting price, reserve price, and duration. Buyers place bids that must exceed the current high bid by a minimum increment.