This is my second time interviewing with Cloudflare (two different positions). And have previous experience doing the job interviewed for at a major global tech giant.
Beware! Very nitchy (and exhausting) hiring process. They're RIDICULOUSLY picky. To get the job, you MUST have a unanimous consensus between all 12+ people you interview with to extended an offer. Odds are pretty good that you will NOT succeed. Many people currently employed by Cloudflare have interviewed multiple times after getting an initial 'No'.
Like others have commented on here, multiple levels of the interview process and they move slower than every other employer you'll ever apply with.
First interview: initial with HR
Second interview: varies. Could be with 1 person (one-on-one) or a panel of 5 people
Third interview: 1 or 2 senior managers
Fourth interview: CEO or C-Level interview
Expect to wait 4 weeks between contact. And the longer you have to wait (towards the end of this interviewing process) means they're interviewing other people and you won't make the cut)
Expect them to be fake through every part of the interview process. They will smile at you, compliment you, and agree with you. Even tell you that they like you and need your expertise. It's all very polite but very superficial. So don't be fooled thinking that this is an indicator that you're doing well. These guys are EXPERT poker players. You will still get cut in the end as 'not a good fit' into their exclusive company culture. So don't buy into the niceties.
They get credit for having a good interviewing policy. It's more conversational and friendly than most places you will interview with. But I'd rather skip all the white-glove service if it means that you get honest feedback during the interview process and a lot less fluff.
To add insult to injury, I keep getting Cloudflare employees contacting me because my experience is 'EXACTLY' what they're looking for. I have to keep explaining that I agree, but the people I interview with at Cloudflare seem to disagree with these managers.
I will no longer consider Cloudflare a viable possible employer in any future job search. I've had enough. I will not recommend any of my colleagues towards Cloudflare, simply because I do not wish anyone to have go through an exhaustive demoralizing experience like I had. I have many other Fortune 500 companies interested in my experience that offer superior culture, perks and diversity.
It's funny I qualify easily for a job at one of the USA's top tech leaders but not worthy of consideration at Cloudflare. What a complete waste of time and energy!