I was put through about 4 rounds of interviews, with the COO, CEO, and a few employees. I invested a decent amount of time into the process and ultimately was told I would be sent an offer letter, which I agreed to. After following up a week later, I was told again the offer letter was coming, but HR had a backlog. A week after that, I followed up again. I was never responded to and no offer letter was ever sent. This was extraordinarily unprofessional and shocking. I believe it indicates the kind of environment one could expect at the company.