#fan-out

5 fan-out interview questions, asked at Meta, Amazon, Google and 3 more companies. Last asked Oct 2026.

Design a real-time trivia battle royale with live spectatorsSystem designDesign a trivia battle royale. A room holds dozens to a hundred or more players. Questions go out round by round; after each round, players who answered wrong and the slowest…
Last asked Oct 2026
Design Instagram StoriesSystem designDesign the stories feature of a photo and video app: users post photos or short videos that their followers can view for 24 hours, after which they disappear. At the top of the…
Last asked Sep 2026
+5
Design a news feedSystem designDesign the home feed for a social network with 1B users: posts from people you follow, ranked, fresh within seconds.
Last asked Jun 2026
Design live comments for live videosSystem designDesign real-time comments on live video broadcasts: viewers post comments and everyone watching the same video sees them appear within a second or two, even when a popular stream…
Last asked Apr 2026
Design live comments for a live streamSystem designViewers post comments on a live video and everyone watching sees them in near real time, including streams with huge audiences. Cover the write path, fan-out to viewers…
Last asked Jan 2026