I agree - if you have any chance at the slightest volume (and based on this we're talking 100 concurrent users, not a million) then you are handicapping yoursel

I agree - if you have any chance at the slightest volume (and based on this we're talking 100 concurrent users, not a million) then you are handicapping yourself if you're stuck on a single thread. Personally I would suggest Elixir (and the Phoenix web framework). It's fully 'parallel by default', will happily saturate all your cores and serve tens of thousands at the same time. The language is simple, the framework is good, although obviously not as many people know Elixir as Python.