It's a five step process. In order to get started you have to answer some questions about your work experience and optionally provide a cover letter, which I strongly advise to do. Second stage is a video questionnaire consisting of five questions. Watching and listening to yourself is the most difficult thing a did in years. :) I did not pass through the second stage, though. Hotjar responded quickly.

Applied online and after around a month I got an email that I am invited to a video call with one of their recruiters. In the call we mostly talked about my experience and I answered some questions the recruiter had and at the end of it I had a chance to ask questions. I was told that they will let me know by next Tuesday, but it has been a couple of weeks already, and I have not heard anything since.