A series of individual interviews with different Backblaze employees which cover programming, design, etc as well as culture and "fit". The emphasis was on understanding the approach to problems and was actually rather fun -- though definitely time consuming. Expect the process to take 5 or so hours overall.

First there's a take home Java assignment where you use BackBlaze's B2 SDK (don't worry, you don't need any prior knowledge) to pull some bucket and file listings, open the file contents, and count the number of times a character appears in each. It takes around 3-4 hours after which you submit it and hear back within a few days from HR. Once I received word they wanted to move forward to a formal interview, they setup a 1:1 coding session for 1-2 hours with one of their engineers. There were 3 coding challenges they wanted to work through, specifically encouraging you to ask questions and collaborate as if you were on an actual job. One question was implementing binary search from scratch. I'll admit it was a little difficult as that's something you do in college and it had been a long time. We went through the coding challenges. HR ghosted me for over two weeks after that. I followed up and only then did I get a "Oh yeah we decided not to move forward" response. They were very communicative up until the point they decided not to make an offer after 4-5 hours of my time.