I applied through another source. The process took three weeks.

The interview process was definitely one of the lengthiest that I've ever experienced. I walked away feeling I had done a lot of consultation for them through the design challenge, which involved writing an algorithm assuming a capability that they didn't have yet but potentially would in the future, and in the series of onsite interviews.

Rounds:

• Call with hiring manager: It was just a chat about my experience and why I was interested in the company. There were no technical questions outside of that.
• Design challenge: They recommended spending two to four hours. With just two hours, you could probably just get through the spec, come up with a half-assed design, and probably just implement that given how involved it was. It obviously wouldn't get you to the next round, so you'd have to put in more time than that. It took me close to two hours to come up with a pretty slick algorithm, and another eight to code, test, and refactor to make it modular and extendable.
• Design walkthrough: If the design looks good, an engineer will go through your solution with you, where you're expected to talk through your design process, highlighting any assumptions you made, the key features you're proud of including, and what you would do to improve it if you were given more time. I was quite proud of my design, especially after hearing that it was something beyond what they currently had in production (red flag, to be honest).
• Recruiter call: The recruiter called to share that I had advanced to the next stage, which was an onsite interview. She went over the interview schedule and a brief summary of what to expect for each round.
• Onsite (six rounds):
• Presentation: I had to give a presentation describing my work experience in the past few years to my onsite interview panel. They pried into the technical details quite a bit, and it felt like I was consulting.
• HR round: I just put on a serious face and spoke about how customer-centric I was throughout all of the behavioral questions.
• Systems Architecture: The two interviewers (tag-team) were quite inexperienced, and I have a feeling this round was my downfall. The task was to essentially draw a diagram of the system while justifying my placement of each of the components. Like system design rounds at any other company, I assumed this was supposed to be a discussion between me and the interviewers rather than me just drawing it all up without much communication. We got through the entire design and even covered a few follow-up questions, so I felt pretty good about it.
• Systems Design (again): The problem posed was smaller in scope than the previous one in that the goal was to design a system around stress-testing a feature component. It felt like I was consulting again since I pulled from my past experiences. I was able to suggest an improvement to their current system, which the interviewer pointed out, so I was feeling pretty good about this round.
• Chat with cofounder: I got stood up for 10 minutes, and I honestly felt a bit disrespected. Otherwise, it was a casual chat about the company.
• Wrap up with hiring manager: It was just a casual talk to discuss how the day went, what I could potentially be working on, and my timeline. Based on our conversation, I was feeling pretty good about the whole experience and was totally expecting an offer.

Results and feedback:

I received a generic email (completely neutral tone, not even an exclamation point somewhere) from the recruiter to schedule a call to discuss the interview result two days after the onsite. From my experience, the majority of companies I applied for rejected me through email, but I have seen on Glassdoor that the company rejects candidates over a call, so I wasn't sure whether it was good or bad news. I thought I had done well, so I was leaning towards positive.

My post-interview feedback was that although I had strong intuition and was technically strong, they were looking for someone who had experience architecting end-to-end systems in a production environment. Apparently, I asked too many questions during the systems architecture round, and they were looking for someone who was able to design with fewer guidance. I felt the interviewers poorly communicated some components, and I had to ask probing questions to fully understand things. They took responsibility for that during the round, but I don't think that was reflected in the feedback. The interviewers were young (in general and in terms of tenure at the company), so that probably worked against me.

Personally, I felt misled from the beginning because it was obvious from my resume and I had also made it transparent to the hiring manager that I lacked the architecting experience. I wasn't going to just develop that technical know-how all of a sudden during an onsite, so that reason didn't sit right with me. The recruiter started stammering at this point, so I didn't push further. Oh well, at least I got a trip to San Francisco out of it.