[james_s_tayler]

I would class your definition as expert rather than senior. It's a level above what I'd expect.

Then again seniority has many dimensions. I often see a lot of senior devs who have mid level skills or mindset but they have become domain experts or experts in the product and seniority is conferred that way. I don't necessarily think that is wrong or undeserving either. I guess if we are talking absent any business/domain knowledge then seniority is judged more closely off raw technical familiarity. For me it's about system design/architecture. Having a strong set of principles that guide your decisions etc.