What happened with the Cloudflare outage — and what we should take away from it On 18 November 2025, Cloudflare, one of the most critical web-infrastructure providers suffered a major global outage. 1. The root cause was a configuration bug: a change in a database permission caused a “feature file” used by Cloudflare’s Bot Management system to double in size. 2. This oversized file crashed core proxy software, triggering widespread HTTP 5xx errors across the network. 3. Services like X (formerly Twitter), ChatGPT, Canva, and even public systems like NJ Transit were affected. 4. Cloudflare identified the problem, rolled back to a safe configuration, and fully restored services by ~17:06 UTC. 5. Importantly: this was not a cyber attack. No malicious activity was found. Key lessons: 1. Dependency risk is real Relying heavily on a single provider means outages ripple across the ecosystem. Multi-provider strategies and graceful fallbacks aren’t optional anymore. 2. Internal changes can be as risky as external threats The failure came from a config update. Validate internal files the way you treat user input: enforce size limits, schema checks, and sanity rules. 3. Rollback and kill-switches must be first-class features Cloudflare recovered fast because they had a known-good state to revert to. Strong rollback paths are crucial for any high-availability system. 4. Transparent communication builds trust Cloudflare clearly explained what went wrong and how they remediated it. Teams should embrace the same openness during incidents. 5. Design for failure, always Even world-class infrastructure breaks. What matters is rapid detection, diagnosis, and response. Invest in observability, chaos testing, and mature incident playbooks. This outage is a great reminder: even foundational, “trusted” infrastructure can fail in unexpected ways. As builders, we must constantly question assumptions, design for redundancy, and prioritize resilience. #CloudflareOutage