eBay / Auction — Notes

Functional

• List item (auction / Buy It Now).
• Bid placement, proxy bidding.
• Live leaderboard, countdown.
• Winner determination + payment + shipping.
• Disputes & buyer/seller protection.

Non-functional

• Strict ordering of bids per listing.
• p99 bid placement < 500 ms.
• Active listings: tens of millions.

Capacity

• 1B+ listings/yr; tens of millions live concurrently.
• Bid storm at auction close: 1000s bids/s on hot items.

Schema

• listings(id, seller, type, start, end, current_high_bid, status)
• bids(id, listing_id, bidder, amount, max_amount, ts) partition by listing_id
• payments(...) similar to Amazon

Trade-offs

• Single-owner per listing is required for correctness.
• Eventual consistency on viewer leaderboard is fine.
• Anti-snipe extension keeps fairness but breaks fixed-time scheduling.

Refs

• eBay engineering blog (Cassandra rollouts, auction architecture talks).
• "Designing Data-Intensive Applications" ch.7 (transactions).
• ByteByteGo "Design an auction".