Low-latency live streaming
Design a low-latency live-streaming platform for interactive broadcasts (creator + chat) supporting 10M concurrent viewers on a single popular stream and sub-3s glass-to-glass latency so the streamer can react to chat in real time. The long tail is millions of small streams. Design ingest, transcoding for live, the distribution path, and how you reconcile sub-3s latency with the CDN scale needed for 10M viewers.
What a strong answer looks like
Clarify scale and constraints first. Propose a clean component breakdown, then go deep on the hard parts (data model, bottlenecks, consistency, failure modes) and name the trade-offs you are making.
Clarify5:30 left
Estimate5:30 planned
Design16:30 planned
Deep dive13:30 planned
Failure9:00 planned
Which questions mattered is sealed until you submit. Telling you now would just be handing over the edge cases.
Run or narrate your approach, then ask the coach.