YOUR BRIEF
What to work through
Work through an online auction as a spoken system design interview. Start by clarifying the scope, sketch a working design and explain the trade-offs behind your choices.
- Post an item for auction with a starting price and an end time
- Bid on an item; a bid must beat the current highest bid
- View an auction with its current highest bid, updated live
- Close the auction at its end time and notify the winner
BEFORE YOU START
Constraints to discuss
- Bids are strongly consistent: two bids never both win
- No accepted bid is ever lost
- Watchers see a new highest bid in near real time
- About 10 million auctions running at once (Hello Interview)
Need a starting point?
Watch for these common gaps as you prepare:
- Reading the highest bid, then writing, without an atomic step
- Telling the bidder a bid was accepted before it is durable
- Every realtime server receiving every auction’s bids
- Closing on a clock that disagrees with the bid service’s
Why this question is in the collection
These sources connect the problem to company interview reports or preparation guides. They do not guarantee what a company will ask you.