How do you go about developing domain expertise?
Other than working "in the business" so to speak, of that domain, I can only thinking of the regular stuff: read books, read articles, watch videos, interview people, etc.
Do you ever do online courses? I've been working through one on FutureLearn about antibiotic resistant bacteria, and rather enjoying it.
It's somewhat subtle and kind of hard to articulate. And I'm still working on developing that domain knowledge myself. But from looking at what's going on here, it's clear that the people who truly understand this system at the highest levels, are the people who understand how it's actually used by customers, and what this stuff means to them. As opposed to the folks who know 'just enough' to write code, but are operating in a bit of a vacuum.
Are there other doors it opens?
Based on my experience here, I'd say that the people who become tech leads, architects, offering managers, etc., are expected to have strong domain knowledge.
Do you ever do online courses?
I do, but most of the ones I've done have been more on the technology side (a lot of data science, math, and machine learning stuff).
I've been working through one on FutureLearn about antibiotic resistant bacteria, and rather enjoying it.
That sounds pretty interesting. I may just check it out.