During the Cloudflare outage, Downdetector was also unavailable. I got details from the team about why they have a hard dependency on Cloudflare, and why that won’t change anytime soon.

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Downdetector went offline during a Cloudflare outage, revealing its dependency on Cloudflare for DNS, CDN, and bot protection. Despite being built multi-region and multi-cloud to detect provider outages, Downdetector maintains this dependency because removing it would dramatically increase costs and reduce performance without generating additional revenue. The team explains that building redundancy at the DNS and CDN layers would require enormous overhead for their mid-sized team, and Cloudflare's bot protection is world-class. They learned lessons about using Infrastructure as Code and traffic shifting during the incident.

Downdetector and the real cost of no upstream dependencies