---
title: "Passing Data to External Forms (Basic)"
slug: "passing-data-to-external-forms"
description: "Learn how to create an ASP.NET-based External Form that retrieves data from Decisions through a POST call."
tags: ["JavaScript", "IIS", "External Data", "Mapping", "HTML"]
updated: 2026-06-04T20:40:44Z
published: 2026-06-04T20:40:44Z
canonical: "documentation.decisions.com/passing-data-to-external-forms"
---

> ## 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.

# Passing Data to External Forms (Basic)

## Overview

The [**External Form**](/version-10/docs/basic-external-form-process) step allows Users to interact with Forms using HTML methods or service calls by passing data into or retrieving data from the External Form. The following article discusses a basic example of passing Data to External Forms utilizing this Step, combined with additional Flow Logic.

---

## Example

In this example, the user will pass data to an external ASP.NET Web Form and displays it as labels on a Form.  
  
Download the following Web Form project file to view a completed project.[Receive-Data-From-Decisions(1).zip](https://cdn.document360.io/6ef8bcc1-6489-4486-9ad1-83acff7e5df0/Images/Documentation/Receive-Data-From-Decisions(1).zip)

1. In a Designer Project, click CREATE FLOW and create a new [Flow](/version-10/docs/creating-your-first-flow-2).
2. In the **Toolbox** panel, navigate to **DESIGNER ENTITIES > FORMS [INTERACTION]** and attach an **External** **Form** step to the **Start** step. On the **Properties** panel under the SERVICE DEFINITION category, click ADD under the **Service Outcomes** field.![](https://cdn.document360.io/6ef8bcc1-6489-4486-9ad1-83acff7e5df0/Images/Documentation/image-1780067129089.png)
3. From the **Add Service Outcomes** window, enter "Done" under the **Name** field and click OK.  
  
When a data return is expected of the External Form, Parameters may be defined in this window.![](https://cdn.document360.io/6ef8bcc1-6489-4486-9ad1-83acff7e5df0/Images/Documentation/image-1780067101685.png)
4. Under **SERVICE DEFINITION > Expose Data On Service**, click ADD. Enter "Comment" under DATA DEFINITION as a **String [Text]** and click OK.![](https://cdn.document360.io/6ef8bcc1-6489-4486-9ad1-83acff7e5df0/Images/Documentation/image-1780067176361.png)
5. Add four more data fields (Company, Email, Name, Phone) as String [Text] under Expose Data on Service.![](https://cdn.document360.io/6ef8bcc1-6489-4486-9ad1-83acff7e5df0/Images/Documentation/image-1780067234685.png)
6. Under the INPUTS category, **Constant** map values for each respective value for the Expose Data On Service. In the **Url** field, enter the URL address with the filename of the External Form that was set up while creating the Virtual Directory in IIS. Connect the Done path to the **End** step. Click **Save** to save changes to the Flow.![](https://cdn.document360.io/6ef8bcc1-6489-4486-9ad1-83acff7e5df0/Images/Documentation/image-1780067293507.png)

---

## Debug

1. On the top action bar, click **Debug**.
2. Click START DEBUGGING.
3. Verify that the information displayed on the Form matches the constant values from the Flow. Click **Done**.  
If using the External Form Example, enter "Done" in Outcome Name and click Send to Decisions.![](https://cdn.document360.io/6ef8bcc1-6489-4486-9ad1-83acff7e5df0/Images/Documentation/image-1743009624912.png)
4. Navigate back to the Debugger. Select **External Form** to view the Input/Output Data.  
The Form Outputs the name of the action, the flowTrackingId, stepTrackingId, OutcomePath name, InstanceName, and the preferedmode.

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