If I understand you correctly, what you’re describing is:
- User fills the form
- Frontend makes an AJAX request specifically to check for uniqueness, and may set an error accordingly
- When frontend says the form is valid, it sends the data to the backend,
- Backend does not bother checking uniqueness in the validation step because that’s already been done, but does react as usual if there’s a constraint violation
That makes sense to me. It’s the same principle, carried further; the user typically can correct a uniqueness issue even before submitting the form.
