Design Online Auction System
Last Updated: December 29, 2025
What is an Online Auction System?
An online auction system is a platform where sellers list items for sale and buyers compete by placing bids within a specified time window. The highest bidder at the end of the auction wins the item.
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The core challenge lies in handling concurrent bids, ensuring fair winner determination, and providing real-time updates to all participants. Unlike traditional e-commerce where prices are fixed, auctions introduce time-sensitive competition that requires careful handling of race conditions and precise timing.
Popular Examples: eBay, Christie's Online, Sotheby's, Heritage Auctions
This system design problem tests your understanding of concurrency control, real-time communication, time-sensitive distributed operations, and consistency guarantees.
In this chapter, we will explore the high-level design of an online auction system.
Lets start by clarifying the requirements: