Experience in the relevant tech stack is a bit of a grey area for determining seniority. I’ll try to highlight a few examples with the following story.

Early in my professional career, my Linux pet projects of the previous 8 years did give me a slight technical edge over other programmers beginning in the corporate Windows development world. And with that Unix-like experience, I started doing projects on the side for macOS AppStore for several years.

When time came for the company to build their first iPad application, my macOS experience helped us navigate that area. When we started doing work for Android, the experience of mobile operating systems in general, were enough to give us a push-start.

When I left my first company after 8 years (as an SE II, or Intermediate) I had left with many skills that the company did not have when I first joined. The hiring manager at the next place could tell that I was Senior (and said so) less than 30 minutes into our interview. My spotty experience in Android landed me a Senior Android developer title - which I excelled at in this company for a few years before politics got in the way.

My job at the next company after that, combined all of my Android, iOS and Windows skills for cross-platform work. This company had mostly only Senior developers, my age or older, but they had the worst practices. Simple source control branching, CI and code review strategies I was taught 10 years prior as a Junior, was practically unheard of at this place.

After a few years of being fed up with that circus, I ditched my whole cross-platform mobile tech stack that I specialized in for the last 8 years. I went back to C++ which I had learned 20 years prior, with only spotty corporate experience with it. I was back on macOS but it has been several years since I wrote anything serious with it. If you do a lot of Apple programming, you know that even 2 years away is a long time because they constantly deprecate APIs and change their provisioning. A Junior with 3 years in this tech stack is probably more up to date than me.

My current employer didn’t hire me for my rusty outdated skills; they hired me for my potential and my maturity. The ability to care about design principles, user experience, test automation, code coverage and the CI pipeline. The soft skills around communication, due diligence and accountability. Skills in tech stack are not as special in comparison.