First call was w/ CTO NOT w/ HR. I manage to talk to HR after I requested a meeting w/ HR. Odd but ok fine I'll play along. I was told a coding challenge would be involved towards the latter stages of the interview process. I hate coding challenges. I think it's a waste of time but I was intrigued by the position so I went along with it. After I got through the first two rounds, the coding challenge came. In the instructions it says to time box yourself, there is no need to complete the entire exercise. In fact, I was told no one has been able to complete the exercise. Next step would be to schedule another round to discuss the work and thought process that went into the coding challenge. So i finally completed the exercise and submitted code that works. A few things didn't work and I clearly outlined what worked and what didn't work. I get an email from the CTO stating that I wouldn't move on to the next round. I emailed the CTO asking for feedback but he ignored me. Next, I emailed HR but figure HR works for the company so why would they care? I'm not upset, in fact I got an offer from another place, which works out a lot better in terms of career growth and money. What pissed me off was not being told why and I was never given the opportunity to discuss my work that I spent hours on for free. When I showed a handful of people the CTO's response (he finally responded), they all said I dodged a bullet. Each person's response was, "wtf does he mean by that?" Sure they're going to be bias but at the end of the day, I should've stuck to my gut and not do coding challenges. If you're a senior engineer with years of experience, do yourself a favor and walk away.