Mock system design interview at Booking.com
A live 45-minute round on a question reported in Booking.com interviews, run by an AI interviewer that asks one thing at a time, probes what you say, looks at your whiteboard, and weighs what that round is reported to weigh. It ends with a debrief: a score, what was strong, what was missing.
Design Ticketmaster
Sell 60 000 seats in ten minutes to a million people at once: hold a seat while someone pays, never sell it twice, and keep the site up when demand is a hundred times supply.
You will not see the requirements, the numbers or the design before you start. That is the point.
What the Booking.com round is reported to look like
About an hour, though some candidates report 90 minutes. Prompts come from the travel business: hotel availability and search, the booking flow, or payments work such as charging a card in scheduled instalments or screening cards for fraud.
What it weighs
- Correctness on the booking path: no double booking, and payment steps that are safe to retry
- Search that can show slightly stale availability, kept apart from a booking that must be exact
- Calls to outside systems, such as payment or fraud providers, and what happens when one fails
The common mistake
Treating search and booking as one problem. Search can afford to be a little out of date but the booking and its payment cannot, and interviewers are reported to probe how two guests are kept from the same room and how a failed step is retried.
From public interview guides and candidate reports, and Booking.com’s own interview guidance where it publishes any. Not endorsed by Booking.com. The interviewer is an AI running in that style; it is practice, not a prediction.
Start the round
The interviewer’s opening question is free. Answering it is part of Pro. See an example round and its debrief →
The 4 questions this round draws from
Each is reported in Booking.com interviews. Pick one to sit, or read its reference design and walk through a strong answer first.
- Design TicketmasterSell 60 000 seats in ten minutes to a million people at once: hold a seat while someone pays, never sell it twice, and keep the site up when demand is a hundred times supply.drawn
- Design AirbnbSearch 7 M listings by place, dates and price, book a stay without ever selling the same night twice, and keep calendars in sync with hosts’ other platforms.
- Design an A/B Testing PlatformRun 500 experiments at once on 300 M users: sticky variants in microseconds, exposure logging, and confidence intervals teams can trust.
- Design a Flight Booking SystemAnswer 50 M searches a day from 20 slow, metered suppliers through a fare cache, then book seats you do not own, exactly once.
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