How should someone with 5 years of industry experience prepare for system design interviews. I am trying to find out what is the expectation for such a candidate. Some people recommend the book - 'Designing Data-Intensive Applications'. Which goes over the issues that you might face and solutions (including some basic techniques) considered to solve them. On the other hand the online contents are often more about what tools you use and somewhat high level. What is the expectation in a real interview? Also how much does it vary from company to company?