Well, I have. With both .net and nodejs. They both do the job fine (you mention 10K LOC, but I’m not sure that you mean because that’s still comfortably tiny

Well, I have. With both .net and nodejs. They both do the job fine (you mention 10K LOC, but I’m not sure that you mean because that’s still comfortably tiny — a one-person app at most, where pretty much anything works.) In my experience they both scale just fine. Your limiting factors are much more defined by your app architecture, dev group politics (as reflected in response to management), and what I’ll call your dev workflow process (how many minutes is it, between when you as a dev make a final, correct source change, and the change makes it far enough that another person can see and evaluate it in the software?)