CSG Software Engineer 2 interview questions

The interview took 3+ week. Started with basic call with HR, codility test which had 2+ technical questions, followed by onsite interview which was 2 hour with senior architects. The onsite interview started with resume review, to technical questions on projects, basic experience questions. It did not include any system design although there were questions around how system can be made more scalable, how to improve performance, what are the factors that needs to be considered for making apis fast.