Got internally referred by email but CTO was not responding, had to apply online. Had an initial interview with HR, which was really nice. Then a technical interview with a bit bossy CTO but in overall good. It was quite complex about my technical knowledge and informative about the company. For the third round there was a coding challenge. Although I put quite an effort to the task and the whole process, I had to remind them to see the result. Then, they just sent a generic email about rejection. Some feedback or at least some reasoning would be fair after the work I believe.

Had a regular preliminary call about the company and role. Backend task was assigned, which was to be completed over a period of one day. After submission, the solution was not evaluated, and no feedback provided (how do I know => github traffic). If you are a seasoned developer, do not waste your time.