I have been contacted by HR department, they had organised Skype call with CTO. The interview was general phone screening interview and we've reviewed my resume. Later on, they sent me code challenge and gave me 1 week for completion, I've completed coding, wrote unit tests, documentation etc. But I couldn't get any response from them. I decided to remind them and emailed to CTO (he was the one who sent code challenge), but I received an auto-generated email that he's not working with the company anymore. After 2 days I emailed to HR department and could receive a reply in a short time, where they were saying that my skill level was not a match for the position. Seems like either they have not checked my source code or it's a short way to send candidate out of the procedure. So it would be better if they could give some feedback or make general code review interview because I was pretty sure that my code was optimised and using correct approach for solving that challenge. Overall impression was negative.