The interaction between the services (connection points) would also pass type checks. (Because they are typed as well) ... so that’s the whole problem domain.

The interaction between the services (connection points) would also pass type checks. (Because they are typed as well) ... so that’s the whole problem domain. No move of goal post. And no, like I said with things like typescript (And flow or Sorbet) you don’t need to compile any binary at all let a lone a single one. Also: a monolith does not refer to a single binary it refers to a single application code base. (You can have monoliths in Ruby/Python/JavaScript/php/etc where no binary is produced) I think you are misunderstanding what I’m saying, because I’m basically saying the same thing again: - service A consumes service B - they are both type checked (as you readily admit) - the call site of service B in service A is type checked as well. - there are 0 points in the code or interactions that are not type checked.