First they sent me a codility technical test where I had to solve 3 problems in 3 hours, the problems were not hard at all. Then I was invited to an online interview with 2 persons, we have talked about a personal project and I had to go through the architecture and DB design, then they started to ask many related thread management questions, data structures and in the end they gave me a linked list problem to find if there is a circle or not.