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How to prevent duplicate values for a form field on 123FormBuilder?

If you want to reject duplicate input values for a form field, you can easily do that by enabling the option Don’t allow duplicate values. You can find it in the Form Editor → Edit Field panel of the form builder after you select a field.

The most relevant use case example is that of unique email addresses. There are situations in which you don’t want to accept duplicate email addresses. If has been used once, it can’t be used again.

Duplicate values

When form users provide input that already exists in your form submissions, they get the following field validation error:

Duplicate value error

The following form fields have the option to reject duplicate values: Short Text, Name, Number, Email, Website, Masked data.

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    1. Hi Simon,

      Yes, you can change any error message on the form.

      To do that, you need to go to Form Settings –> Translations.

      Once you are there, add the English language for example, and click on customize.

      A lightbox will pop-up and in that lightbox, you should see the tab for System Messages.

      Simply right in the box next to the Message what you want to see instead and hit save.

      If you experience any issues or difficulties, please contact support either through Live Chat or at

      Have a great day!

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