I was contacted by a recruiter and completed a HackerRank challenge (the same Grid Illumination question that several other candidates also received). Although I performed poorly on the challenge, I was contacted about a week later for a one-hour phone interview.

Several days after that, I received an email from my recruiter to schedule an onsite interview. This consisted of three one-hour interviews, lunch, and a product demo.

I'll note that among the interview questions (phone and onsite), I encountered a couple that others had shared on Glassdoor, which I've included below.

Overall, the interview process was very smooth and enjoyable. However, the questions I was asked were by far the hardest I encountered this recruiting season (harder than those from Google, Facebook, etc.).

My recruiter was incredibly prompt and accommodating, and they genuinely seemed to care about the candidates they were working with. Additionally, all the engineers I met were highly skilled during the interviews, very friendly, knowledgeable, and appeared to truly enjoy working at Dropbox.

Develop a system to count web hits in the last 5 minutes.

Write a web crawler (follow-up question: make it multithreaded).