THE CANVA OUTAGE: ANOTHER TALE OF SATURATION AND RESILIENCE

Summary from the TLDR Web Dev newsletter

Canva experienced a major outage triggered by a seemingly innocuous deployment of a new editor page. A stale Cloudflare traffic rule misrouted user traffic over the public internet, causing latency and a backlog of 270,000+ requests for JavaScript files. This led to a "thundering herd" effect, overwhelming Canva's API gateway with 1.5 million requests per second. Canva engineers mitigated the outage by manually increasing capacity and using Cloudflare's firewall to temporarily block traffic.