HR approached me and had an one hour phone interview explaining the position. After 3 weeks(they forgot to sent the email) they sent me a link for HackerRank with 5 questions quite challenging for 1.5 hours. They never sent me a response after that.

I was interviewed for the Athens division. The interview was divided in three parts. First, an online skill test where you had to solve at least 3 of 5 medium difficulty problems in your preferred language in a solid way. Second, a telephone technical interview that covered a variety of fields that required your basic knowledge. Third, if you passed this interview, a 3-hour technical and CV interview in company's premises. There you had also to solve 2-3 problems and present yourself. A part of this last interview was held in English.