There was first an HR screening, then case study then an interview in person with the cofounder.
After I passed all the stages and had the last interview with one of the co-founders. First of all, even though it was an on-site interview which means I had to take time off from my work to go, he didn't even let me speak much, instead told me what he does. He gave me an offer at the end of the interview, which is pretty low for Hamburg standards. When I politely explained that this offer is pretty low especially for Hamburg and my qualifications, he directly told me there is another candidate who has similar qualification and background "who went EVEN LOWER than this salary, so it's up to me if i want to take it or not"
When I said, I am not willing to accept the offer, he told me "Thank you for your time and see you bye" . It was the most UNPROFESSIONAL attitute I have seen so far in a start-up. They are looking not for talent but only for cheap people. If you want to work in a chilled startup enviroment, but be hired because you are cheap, you should go ahead!