How to Prevent Duplicate Submissions in OpnForm Using “Exists in Submissions” Validation?
Want to make sure users don’t submit the same information twice? OpnForm’s “Exists in Submissions” custom validation now works for almost all field types, helping you keep your form data clean, organized, and reliable.
With this feature, you can block duplicates for emails, numbers, URLs, select fields, multi-selects, dates, users, relations, and more — automatically.
✅ Step-by-Step Guide
- Open your form: Log in to your OpnForm account and go to the Forms section. Select the form you want to edit.
- Select a field to validate: Find the field you want to ensure is unique and click the ⚙️ settings icon.
- Open Custom Validation: In the right-hand panel, go to Custom Validation.
- Add the “Exists in Submissions” rule:
- Click Add Condition.
- Choose “Exists in Submissions” to prevent duplicates.
- Set a custom error message: Write a friendly message that will appear if someone tries to submit a duplicate value.
- Publish your form: Click Publish to save your changes.
📝 Supported Field Types
You can now apply “Exists in Submissions” to nearly all OpnForm fields:
- Title
- URL
- Phone number
- Rich Text
- Number
- Select
- Multi Select
- Status
- Date
- User
- Relation
⚠️ Note: Some complex fields like User or Relation may require linking to a database to validate properly.
💡 Tips for Using “Exists in Submissions”
- Emails & Usernames: Perfect for signup forms or registration forms where each entry must be unique.
- Numbers or IDs: Prevent duplicates in surveys, order forms, or membership forms.
- Select & Multi-Select Fields: Ensure users pick options that haven’t already been chosen in previous submissions.
- Relation Fields: Keep linked database entries unique across multiple forms.
✅ Benefits
- Automatically prevents duplicates without manual checks.
- Works across most fields in your forms.
- Lets you show custom messages to guide users when duplicates are detected.
- Keeps your database clean and reliable.
If you want, I can also draft a small visual example for this help page, showing a form field with a value being validated — similar to a screenshot — to make it even more beginner-friendly.
Do you want me to do that?
Updated on: 06/02/2026
Thank you!