Went through this two months ago for a senior SWE role targeting L4/L5. I had four rounds in one day via Zoom. Here's the breakdown:
Round 1: Coding. Standard LC-medium difficulty, CoderPad, 45 minutes. Mine was a modified interval merging problem. They care that you talk through your approach first and handle edge cases. The interviewer gave hints when I was stuck, which I didn't expect. Not adversarial at all.
Round 2: System design. This is where Cloudflare diverges from the standard FAANG template. The scenario was: design a globally distributed rate limiter. Which, if you know what Cloudflare does for a living, is not random. Expect system design questions tied to their actual product surface. If you've never thought about CDN architecture, edge compute, anycast routing, or DNS at scale, you will feel undercooked. I was fine because I'd read a few CF blog posts about their infrastructure. Seriously, read their blog. It's good and it's basically prep material.
Round 3: Behavioral. Covered in another thread here. Two interviewers. Structured STAR format questions. About 40 minutes.
Round 4: Hiring manager. Conversational but don't be fooled. They're still evaluating. Questions like 'what would you build in your first 90 days' and 'what's a technical decision you regret.' Probe for your depth of conviction.
Debrief timeline: got the verbal offer 8 business days after the loop. The wait was rough but they did say decisions take about a week.
One thing nobody mentioned to me: they have a strong culture of internal tools and Rust/Go. If you've only ever written Python or Java and have no exposure to lower-level systems thinking, the system design round will be a gap. Not impossible to overcome but know what you're walking into.