For something like input field validation, a request per keystroke might be a bit much, but the update rate of feedback users expect. In systems with frontend

For something like input field validation, a request per keystroke might be a bit much, but the update rate of feedback users expect. In systems with frontend UX validation and backend functional validation, errors from the backend tend to be aimed at devs. I.e. might expose the reflex that's known good over having nice words for the approximate test done in the frontend.