@harikt As far as I can see, the only thing you need is to create a custom rule for the unique value: https://github.com/auraphp/Aura.Filter#creating-and-using-custom-rules The purpose of this filter should be to **NOT** try to save invalid data in the first place.

But with the suggested extension of the `ConstraintViolationList` you will get an easy way to accomplish your goal, just not in the model itself, but somewhere more sensible from design perspective. Your code will change only slightly.