tl;dr - slow, tedious, and repetitive
I applied online and 2 weeks (!) later was contacted by a recruiter to setup a phone screen which took place the next day. The phone screen was essentially asking what I know about Cloudflare, the job etc. Standard initial screening.
1 week later I had another phone interview with the department head which went very well despite them being late to the call (especially a problem when you're staying up late at night to have a call with San Francisco). This interview went well and was asking about my prior experience, more details about the role, and opening up the line for any QA. All positive so far.
3 weeks later, in which time I sent multiple follow ups to see if there had been any advancements, I was finally invited for an on-site interview with 4 members of the Cloudflare team which took place the week after. Each of the team members I met were very courteous, transparent, and asked useful questions. Despite this, I was repeating myself 4 times over the 2 hour interview as the same questions were being asked to me.
3 weeks later, and, you guessed it, in which time I sent a follow up reminder, I was finally contacted to say they wanted to invite me on-site, again, to deliver a mock presentation with a few members of their team. I spent a long time preparing the presentation including a lot of research, and using the Cloudflare product extensively to understand it's full potential. Not all of the invited team members turned up to the interview - not an issue, I delivered it regardless. It seemed to go well, but wasn't really the most conventional of scenarios.
Following the second on-site interview, I sent 2 follow up emails over the course of 2 weeks and had no reply.
Nearly 2 weeks later, over 3 months since the initial application, I was finally contacted to say Cloudflare wouldn't be continuing my application. Disrespectfully, I received no feedback and no insights - nothing. An extremely disappointing process and it left me with a bitter taste in my mouth.
Notably, I was never really asked about my personal life, my interests outside of work or any other non-Cloudflare related topics. This probably reflects other reviews on Glassdoor where the culture is extremely work, work, work.
They said hindsight is 20/20 and looking back, I'm relieved I'm not working at Cloudflare and am now happily employed at another company.