#real-time

18 real-time interview questions, asked at Amazon, Meta, OpenAI and 9 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 a real-time multiplayer typing raceSystem designDesign an online typing race. Each race has 2 to 8 players. When the race starts, every player gets the same generated passage and types it; the first to finish the whole passage…
Last asked Oct 2026
Design a distributed power grid control systemSystem designMonitor and control generators, substations and loads across a power grid, reacting to failures and demand changes in seconds, safely, even when parts of the network are cut off.
Last asked Sep 2026
+4
Design an online chess gameSystem designMatch players of similar rating, play live games with clocks, handle disconnects and reconnects, and keep game history and ratings.
Last asked Sep 2026
Design a real-time comment feed with optimistic updatesSystem designDesign the front end of a comment section where other people's comments arrive live and the viewer can post their own. The focus is optimistic posting: a submitted comment shows…
Last asked Sep 2026
Design a matchmaking service for an online gameSystem designDesign a matchmaking service. It must let players join the queue and cancel, match two compatible players, notify both when a match is found, and deal with disconnects and…
Last asked Sep 2026
Design a global one-to-one voice calling systemSystem designDesign voice calls between registered mobile users worldwide, at millions of users. A caller rings another user, the callee gets an incoming-call notification and accepts or…
Last asked Sep 2026
+3
Design UberSystem designRiders request trips, nearby drivers get matched, and both see live location until drop-off, with pricing and payment, for millions of trips a day.
Last asked Sep 2026
Design real-time comments on a design canvasSystem designLet people pin comments to points and objects on a shared design canvas, reply in threads, and see each other's comments live as the design changes underneath them.
Last asked Aug 2026
Design a food delivery platformSystem designDesign the backend of a food delivery app: customers browse nearby restaurants and order, restaurants accept and prepare the order, and a courier is assigned and tracked live…
Last asked Jun 2026
Design human avoidance for warehouse robotsSystem designDesign how robots in a warehouse detect and avoid the people working on the same floor: sensing, what each robot decides on its own versus what a central system decides, and…
Last asked May 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 an online auction with live biddingSystem designDesign an auction system where users bid on items (for example items posted on a social app) and everyone watching sees the current highest bid in real time until the auction…
Last asked Feb 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
Design an online Minesweeper platformSystem designDesign a platform where people play Minesweeper online. Cover generating boards, the API for revealing and flagging cells, where game state lives and who is trusted to know mine…
Last asked Nov 2025
Design an online auction serviceSystem designDesign an auction feature inside a social app: sellers list an item with an end time, buyers place bids, and everyone watching sees the highest bid update live. Cover the data…
Last asked Oct 2025
Design the front end of a desktop AI chat appSystem designDesign the client side of a desktop chat app for an AI assistant: the conversation list, the chat view and the model's replies as they stream in. This is a front-end system design…
Last asked Sep 2025
Design a real-time air traffic control systemSystem designTrack every aircraft in a region from radar and transponder feeds, predict conflicts, and alert controllers within a second, with no single point of failure.