---
title: "Validating Form Data with a Flow"
slug: "form-validation-flow"
description: "This document demonstrates how to validate Form Data via a Validation Form.  Validation Forms evaluate input Data, and output the data or information on why the input is invalid. "
tags: ["Dynamic Behaviors", "User Experience"]
updated: 2025-06-17T15:23:14Z
published: 2025-06-17T15:23:14Z
canonical: "documentation.decisions.com/form-validation-flow"
---

> ## Documentation Index
> Fetch the complete documentation index at: https://documentation.decisions.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Validating Form Data with a Flow

## Overview

**Validation Rule** may choose to build their logic within a Flow rather than as a Rule.

Rules creating with a Flow source extends Flow Validation Rules' capabilities to allow for more advanced validations. After evaluating the inputs, a **Validation Flow** would return a collection of issues that contain data about which Form control producing errors.

Unlike Rule Validations, Flow Validations cannot be applied to Form Layouts (i.e., a Grid).

---

## Example

1. In a Designer Folder, create and name a new Flow. It will automatically open in the Flow Designer.
2. After the **Start** step, add a **Show Form** step from the **Favorite Steps** category. Create and name a new Form. It will automatically open in the Form Designer.
3. Add a Check Box control to the Form named 'I under Terms and Conditions' and a Button named 'Done'.
4. In the Form's Properties > Form Rules, select ADD next to **Validation Rules** to create a new validation rule.  
![](https://cdn.document360.io/6ef8bcc1-6489-4486-9ad1-83acff7e5df0/Images/Documentation/2025-06-17_10h25_14.png)
5. In the **Add Validation Rules** dialog, name the validation and change the **Validation Source** to **Flow**. Select PICK OR CREATE FLOW and create a new Flow.  
![](https://cdn.document360.io/6ef8bcc1-6489-4486-9ad1-83acff7e5df0/Images/Documentation/2025-06-17_10h27_33.png)
6. In the Form Validation Flow, select SETUP INPUT DATA. Type **CheckBox** as the Name and change the type to **Boolean**.  
![](https://cdn.document360.io/6ef8bcc1-6489-4486-9ad1-83acff7e5df0/Images/Documentation/2025-06-17_10h30_48.png)
7. Add a **Value is True** step from the **Rules >** **System Defaults > Default Form Validation Rules** category.
8. With the step selected, navigate to the **Properties** panel. Under **Inputs > Value**, select **CheckBox** from the Flow.  
![](https://cdn.document360.io/6ef8bcc1-6489-4486-9ad1-83acff7e5df0/Images/Documentation/2025-06-17_10h32_43.png)
9. Connect the **True** outcome path to the **End** step.
10. On the **False** outcome path, add a **Create Data** step. View the **Create Data's** **Properties** panel and select SHOW EDITOR.  
  
Type **Validation** as the Name and search for and select **FormValidationIssues** as the Type. Select CLOSE to save and close.  
![](https://cdn.document360.io/6ef8bcc1-6489-4486-9ad1-83acff7e5df0/Images/Documentation/2025-06-17_10h37_54.png)
11. For the **Validation** input, change the mapping type to **Constant**. Select the pencil icon to open the **Edit** dialog.
12. In the **Edit** dialog, under **Settings**, check **IsBreakingIssue**. Under **Validation**, set the **Break Level** to **Fatal**, type a **message**, and type the Checkbox control's **Data Name**. Select OK.  
![](https://cdn.document360.io/6ef8bcc1-6489-4486-9ad1-83acff7e5df0/Images/Documentation/2025-06-17_10h40_15.png)
13. Connect the Create Data step to the End step. Select the End step. Under **Inputs > Form Validations**, choose **Validation**.
14. Save and close the Form Validation Flow.  
![](https://cdn.document360.io/6ef8bcc1-6489-4486-9ad1-83acff7e5df0/Images/Documentation/2025-06-17_10h43_45.png)
15. Back in the **Add Validation Rules** dialog, select UPDATE INPUTS. Under **Rule Inputs**, select the pencil icon next to **CheckBox**.
16. In the **Edit Rule Inputs** dialog, change the **Input Type** to **Form Component**. Select Terms and Conditions for the **Form Data Name**. Set **RunOnValueChanged** to true. Select OK to confirm.  
![](https://cdn.document360.io/6ef8bcc1-6489-4486-9ad1-83acff7e5df0/Images/Documentation/2025-06-17_11h10_56.png)
17. Back in the **Add Validation Rules** dialog, under RULE EXECUTION, select **Run Rule On All Outcomes**. Under **Triggers,** select the Terms and Conditions Check Box.
18. Select OK. Save and close the Form Designer.  
![](https://cdn.document360.io/6ef8bcc1-6489-4486-9ad1-83acff7e5df0/Images/Documentation/2025-06-17_11h12_52.png)

### Debug

1. In the **Flow** **Designer**, select **Debug** in the top action panel. Select START DEBUGGING.
2. The Debugger will display the Form. Select the **Done** button to attempt to close the Form without the Terms and Conditions selected.
3. The validation warning and red boxes will show. Set the **CheckBox** to **True** and close the Form.  
![](https://cdn.document360.io/6ef8bcc1-6489-4486-9ad1-83acff7e5df0/Images/Documentation/2025-06-17_11h21_02.png)

---

For further information on Forms, visit the [Decisions Forum](https://community.decisions.com/categories/Forms).