In my opinion hiring process at Personio is unprofessional (for the record, all people were nice and polite). It is very long, and in my opinion doesn't respect candidate time. First step was coding challange, which is actually called "brain teaser". I spent few ours on it, to discover later on that actual coding challange is still waiting for me. More than one week after solving "brain teaser", there was a short interview with HR, and then one week later first interview with an Engineering Manager. After that I got an email with the real coding challange, where in the email is stated that should take couple of hours. But there is no way anybody could actually solve it in a couple of hours. 9 days after sending a coding challange, I had an another meeting with an Engineering Manager, to review my code. Some time later I was invited to the interview in the office (with team members, CTO, etc.). It took around 1,5 hours. 6 days after I finally got a feedback, that my application is declined, which is fine, happens to everybody. What I find unacceptable is inviting a candidate to the interview in the office, and after that sending him feedback like: "coding challenge was slightly below the objectives". And second, if you ask the candidate during the interview where does he see himself, and he tells you that in 2 or 3 years he could aim for Team Lead position, it is weird to give a feedback like "Moreover, we feel that we will not be able to accommodate your ambitions to become a teamlead/techlead in the near/mid future and we do not want to offer an opportunity that will not allow you to grow as much as you would like to.". Especially that company has huge plans to hire. To summarise. Whole process took almost two months. Could be definitely shorter by two weeks. And feedback could be honest, instead of some automated response.