Folks preparing for system design — read this real Cloudflare outage & learn why resilience matters
Interview Experience
If you're preparing for system design Design, here’s a real-world lesson worth studying. On 18th Nov, a tiny database permission change at Cloudflare silently broke assumptions… and took down **
Full Details
If you're preparing for system design Design, here’s a real-world lesson worth studying. On 18th Nov, a tiny database permission change at Cloudflare silently broke assumptions… and took down 20% of the internet for nearly 4 hours. It wasn’t a DDoS attack. It was one missing filter in a SQL query. 📌 Good read for anyone preparing for system design interviews or building distributed systems: <a href="https://roundz.ai/blog/postmortem-deep-dive-cloudflare-november-2025-outage)
About This Question
This is a candidate experience report from a cloudflare interview for a swe role during the system design round reported in 2025.
It covers the following topics: Sql, System Design .