Site Reliability Engineer Interview Experience at Cloudflare – 2026

Recruiter screen focused specifically on on-call experience, given Cloudflare's edge-network scale means incidents can have outsized, highly visible impact. Recruiters typically ask directly how many people are on the candidate's current on-call rotation and how frequently they personally get paged.

A deep dive into DNS resolution behavior, starting from a client's recursive resolver query down through root, TLD, and authoritative name servers, and then specifically how a CDN handles cache invalidation across globally distributed edge nodes when an origin's content changes. Interviewers typically ask whether a candidate would favor a short TTL with frequent revalidation or a long TTL with an explicit purge API call, and want the tradeoff reasoning (short TTL costs more origin load, purge APIs require the origin to remember to call them) rather than a single 'correct' answer.

Candidates are asked to design a monitoring and failover strategy for a partial network partition affecting a subset of edge locations, explicitly without taking the entire global service down. A strong approach proposes health-check-driven traffic steering away from the affected edge locations combined with anycast routing naturally redirecting client requests to healthy nodes. Interviewers push on how to distinguish a genuine partition (affected nodes should be pulled from rotation) from a brief, self-resolving blip (pulling nodes too aggressively causes unnecessary churn and cascading load onto remaining nodes).

Discussion of a past major incident the candidate handled: detection time (how the issue was first noticed), the immediate mitigation steps taken, full resolution, and the concrete postmortem action items that came out of it. Interviewers specifically ask which of those action items were actually completed versus which stalled - testing for honesty about follow-through, not just the incident story itself.