System design interviews

Design production systems on a shared whiteboard. Start with Social Media Feed — Owl already knows that conversation.

45 min

Design a URL Shortener

EasyTopicsAPIs · Databases · CachingCompaniesAmazon · Google · Meta

Design a URL shortener like Bitly. Users submit a long URL and receive a short code that redirects to the original.

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50 min

Design a Social Media Feed

MediumTopicsNews Feed · Caching · Fan-outCompaniesMeta · Google · X

Design the news feed for a social platform like Instagram or X. Users create posts, follow others, and open a home feed of recent posts from people they follow.

Start interview
50 min

Design a Chat System

MediumTopicsMessaging · WebSockets · RealtimeCompaniesMeta · Slack · OpenAI

Design a chat/messaging system like WhatsApp: one-to-one messages, group chats, delivery/read receipts, and offline delivery.

Start interview
55 min

Design a Video Streaming Platform

HardTopicsObject Storage · CDN · TranscodingCompaniesGoogle · Netflix · Apple

Design a video platform like YouTube: upload, store, transcode, and stream to millions of concurrent viewers.

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55 min

Design a Ride-Sharing System

HardTopicsGeo · Matching · RealtimeCompaniesUber · Lyft · Microsoft

Design a ride-sharing system like Uber: riders request trips, nearby drivers are matched, locations update in real time, and ETAs are computed.

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45 min

Design Typeahead / Autocomplete

MediumTopicsTries · Caching · Prefix SearchCompaniesGoogle · Amazon · Meta

Design a typeahead / autocomplete system. As the user types, return ranked prefix suggestions in under ~100ms.

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45 min

Design a Rate Limiter

MediumTopicsDistributed Systems · Redis · AlgorithmsCompaniesAmazon · Google · Stripe

Design a distributed rate limiter that enforces per-user or per-API quotas across many servers without becoming a bottleneck.

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55 min

Design File Sync / Dropbox

HardTopicsSync · Chunking · Conflict ResolutionCompaniesDropbox · Google · Microsoft

Design a file sync service like Dropbox or Google Drive: upload, download, multi-device sync, and conflict handling for concurrent edits.

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55 min

Design a Web Crawler

HardTopicsCrawling · Queues · Distributed SystemsCompaniesGoogle · Amazon · Microsoft

Design a distributed web crawler that discovers URLs, fetches pages politely, stores content, and keeps the frontier fresh.

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50 min

Design a Notification System

MediumTopicsPush · Fan-out · QueuesCompaniesMeta · Apple · Google

Design a multi-channel notification system: in-app, push, email, and SMS — with fan-out, preferences, and delivery tracking.

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