If you are senior in coding, you must be attending some high-level design questions. Basically, most of the questions will be asked to get your understanding on, how to scale applications and to analyze what will be so hard for you while analyzing arbitrary large-scale problems. If you can find out a systematic approach in solving the problems, you can get through the interview.

Moishe Lettvin says, “The basic thing I'm looking for when I'm interviewing is not a bag of buzzwords the candidate uses or the experience that's on their resume or their self-described "biggest weakness" -- what I want to know is: does the candidate know how computers work, and can they use that knowledge to write code or design systems to solve problems well. Maybe sometimes a candidate doesn't know the "perfect" data structure for a problem, but if he or she can build up that data structure from first principles, that is extremely valuable. Or, maybe the candidate has a wealth of experience but can quickly see what's relevant and discard that which isn't.”

Adding to this, he has mentioned practicing to write programs on a whiteboard will help you. He suggests you to get used to think on whiteboard, so that your interviewer can easily understand how your thought process works.