Code Room
System designHardsd-g488
Subject Live streamingLevel Senior–Staff~45 minCommon in Distributed systems interviewsIndustries Technology, Software development

Question

Design the edge delivery layer for Low-Latency HLS (LL-HLS) for sports/event streaming reaching 50M concurrent viewers with ~3s glass-to-glass latency over standard HTTP CDNs (not WebRTC). The challenge: LL-HLS works by chunking segments into tiny partial segments and using blocking playlist reloads + preload hints, which generates a storm of tiny, frequently-changing manifest and partial-segment requests that ordinary HTTP CDN caching handles badly. You need the latency of WebRTC-ish delivery while keeping the cacheability and scale of HTTP.

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.

Narrate your design
Loading whiteboard…
Run or narrate your approach, then ask the coach.