This is one of those few instances where getting the technology choice right actually has an impact on cost of operations, service reliability, and overall experience of a product. For like 80% of all the other cases, it doesn't matter what you use as long as your devs are comfortable with it.
Not sure why this comment saw a couple downvotes earlier. mbesto is correct: for most startups, most of the time, competitive advantage doesn't come from the underlying tech stack. To make a general statement, most things could be done similarly on any of several platforms. However, when product requirements match exceptionally well with a specialized technology, you can see things that would simply be infeasible or extremely tough using a different stack.
WhatsApp + Erlang was one of those cases (watch this talk and imagine trying to recreate that system with only a handful of server engineers using any other tech: https://www.youtube.com/watch?v=c12cYAUTXXs). Discord + Elixir appears to be another.
Curious if anyone has any examples that spring to mind from outside the highly concurrent messaging space.
