System architecture

Production systems on a shared whiteboard — start with Social Media Feed.

Session mode

Questions

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

Design the news feed for a social platform like Instagram or X. Users create posts, follow others, and open a home feed …

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

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

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

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

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

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

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

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