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# 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

1. **Open your form:** Log in to your OpnForm account and go to the **Forms** section. Select the form you want to edit.  
2. **Select a field to validate:** Find the field you want to ensure is unique and click the **⚙️ settings icon**.  
3. **Open Custom Validation:** In the right-hand panel, go to **Custom Validation**.  
4. **Add the “Exists in Submissions” rule:**  
* Click **Add Condition**.  
* Choose **“Exists in Submissions”** to prevent duplicates.  
5. **Set a custom error message:** Write a friendly message that will appear if someone tries to submit a duplicate value.  
6. **Publish your form:** Click **Publish** to save your changes.


![](https://storage.crisp.chat/users/helpdesk/website/-/1/b/5/b/1b5b982fc3df6500/chromezhssj0qe4a_1vfc7tj.png)



## 📝 Supported Field Types

You can now apply “Exists in Submissions” to nearly all OpnForm fields:

* **Title**  
* **Email**  
* **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**.




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