How Zoom Scaled Under Pandemic Load: An Architecture Case Study

Tech · 7 min read

Zoom's architecture separates signaling from media plane to enable rapid scaling. The company leaned on software-based MCU and SFU topologies, dynamically shifting participants between routing modes to optimize bandwidth and CPU usage across meeting types.

To maintain quality, they invested in global PoPs and adaptive bitrate algorithms that consider both client metrics and regional congestion. Connection fallbacks and codec negotiation helped degrade gracefully on poor networks, and client-side forward error correction smoothed short packet loss bursts.

Reliability engineering centered on automated failover, capacity forecasting, and observability. The teardown highlights investments in synthetic traffic testing, real-time alerting for tail latency, and staged rollouts for feature flags to avoid cascading failures when deploying changes at extreme scale.