I won't go into the same details as every one else. The only thing I'll say is you're probably going to get your time wasted with this interview process. Initial encryption coding challenge before speaking with a human, a lengthly take home challenge (I spent 20 hours on mine), then an interview to add MORE features to it live, then a "culture" interview, only to be told that they want someone more senior (after passing all technical screenings). Interview process is not difficult, just designed to completely waste your time.

My number one immediate red flag for companies I apply for is when they send an assessment to take before speaking with a human. Complete disrespect of candidates' time. I applied for a Frontend Engineer role and was immediately greeted with an invite to take their assessment. I normally would have just ignored it and moved on with applying elsewhere but I decided to go for it and give them the benefit of the doubt. The assessment isn't terribly difficult but it's by no means easy nor quick. It was basically a coding puzzle, where you need to decode encrypted paths to find the next endpoint. The e-mail states that it should take you no longer than 30-45 minutes. This is simply not the case at all and frankly companies should quit suggesting how long these assessments take. Unless you work with encryption regularly, you are most likely looking up a lot of encryption methods to figure out what you need to do, which takes time and trial and error. I stopped working on it after a few hours when I decided to research the company a bit and found all these negative reviews. I won't be continuing with the assessment now that I see that other candidates, despite completing the assessment fully, did not move on to the phone screen.