So, I've been promoted to Senior Engineer in the last couple of months and that felt really good because I felt that people recognized my efforts to progress and that my dedication paid off.
The problem is that, as a senior, I am supposed to become more part of the recruitment processes, through code review candidates applications, interviewing, etc. All fine by me, but sometimes I get haunted by the too familiar Imposter Syndrome when looking at the code submissions of some candidates for some of the challenges we ask them, I am supposed to be evaluating people that in some cases have (at my eyes) solutions that I would not be able to implement in such detail or finesse and some times I end up spending some hours going through some solutions just to grasp everything that a candidate has done.
Am I an imposter or is this just another phase of the process?
I see it as a different skillset. You possess skills to cut maintainable code, work through issues (technical and people), and whatever other traits the organisation sees you doing well in, or have the potential to. That is quite different from interviewing, which is often just about impressing people enough to let you in the door. I say this having gone through the same process. If you're that worried, study the code as you're already doing, grind leetcode, or my preference - pick up harder problems and run with them. You'll learn some new stuff, maybe build something cool and feel a bit less like an imposter.