Build systems that deliver messages in milliseconds and keep millions of users in sync simultaneously
Design real-time messaging for 1B+ users with group chats, read receipts, media sharing, end-to-end encryption, and cross-device sync.
Design real-time commenting for live events handling 500M+ concurrent viewers with content moderation and sub-second delivery.
Design a video platform like Zoom with WebRTC, SFU architecture, screen sharing, recording, and support for 1000-participant meetings.
Design a Slack-like platform with channels, threads, file sharing, search across millions of messages, and third-party integrations.
Design collaborative editing with Operational Transform, real-time cursor sync, version history, comments, and offline support.