In total three Skype interviews - one with HR manager, one with each CEO and then Trial Days at the office in Berlin. The calls with CEOs were very casual and interesting but they did not differ from each other - I'm not sure why couldn't it be just one call with both of them. Trial days are amazing opportunity for you to know the company better. Everyone is very helpful and basically everything is made for you. Sometimes I felt there is too much activities planned non related to your trial task so at the end you don't have as much time to complete them as you would want to.