---
title: "Calling a Flow as a REST Service"
slug: "rest-handling-services"
description: "Learn how a Flow can be made into a REST Web Service that supports either HTTP GET or POST methods. Calling a Flow as a REST Service allows external applications to send data into Decisions for use in a Flow."
tags: ["Session", "REST Service", "Flows", "API", "Rest integration"]
updated: 2026-07-01T14:44:09Z
published: 2026-07-01T14:44:09Z
canonical: "documentation.decisions.com/rest-handling-services"
---

> ## 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.

# Calling a Flow as a REST Service

## Overview

A Flow can be made into a **REST Web Service** that supports either HTTP GET or POST methods. Calling a Flow as a REST Service allows external applications to send data into Decisions for use in a Flow. The new data can be returned once acted upon or evaluated in a Flow. REST calls to a Flow require either a valid User Session ID or a valid User Authentication ID. The **REST Service API** shows instructions for calling the Flow and the Output. The actions menu for the Flow provides REST service call URLs that are already populated with the necessary parameters.

[Embedded content](https://www.youtube.com/embed/ZBYgItB4chA)

---

#### Prerequisites

- Configuration of Designers (Flows, Rules, Reports, etc.) to allow integrations. For more information, see [View Integration Details](/version-10/docs/view-integration-details)

## Example

A POST method will pass data into a Flow using the REST service call in this example.

1. From a Designer Project, click [CREATE FLOW](/version-10/docs/create-flows) from the **Global** **Action** **Bar**.
2. Select the **Start** step on the workspace. On the **Properties** panel, click SHOW EDITOR under the FLOW INPUTS category. ![](https://cdn.document360.io/6ef8bcc1-6489-4486-9ad1-83acff7e5df0/Images/Documentation/image-1780082699587.png)
3. Under NAME enter "FirstName" and "LastName" as **String [Text]** Types**.** Click **Save** and close the window.![](https://cdn.document360.io/6ef8bcc1-6489-4486-9ad1-83acff7e5df0/Images/Documentation/image-1782916942878.png)
4. Connect the Start step to the **E****nd** step. Select the End step and click SHOW EDITOR under the DATA category. Enter "Output" as a String Type. Click Save and close the window.![](https://cdn.document360.io/6ef8bcc1-6489-4486-9ad1-83acff7e5df0/Images/Documentation/image-1780082827833.png)
5. Under **Properties > INPUTS > Output**, change the mapping from **Unknown** to **Merge Plain Text**. Click the pencil icon to show the editor.
6. Enter "Data was posted to Flow" from the Merge Text Editor window window. Enter "First Name:" hover over the **First Name** in the **Data** section, and click the plus sign. Enter "Last Name:" and add **LastName** by selecting the plus sign next to it. Click SAVE.

![](https://cdn.document360.io/6ef8bcc1-6489-4486-9ad1-83acff7e5df0/Images/Documentation/image-1780082893611.png)
7. Click **Configure** **Integration** on the top right of the Designer. Under **Integration Type**, select **API** **Service**. Next, enable **Configure HTTP Methods**, select POST and GET from under **Allowed HTTP Methods**, and click DONE. Save and close the Flow.

![](https://cdn.document360.io/6ef8bcc1-6489-4486-9ad1-83acff7e5df0/Images/Documentation/image-1780082953393.png)
8. Back in the Designer Project, locate the previously created Flow. Right-click and navigate to **OTHER** **> Advanced > View Integration Details**.![](https://cdn.document360.io/6ef8bcc1-6489-4486-9ad1-83acff7e5df0/Images/Documentation/image-1782917031358.png)
9. The View Integration Details Page will open. Under **Setup**, select **Use Current Session ID**, and click **Additional Options**.
10. Select the Data Format to **XML** to allow for **XML Serialized Input** and set the **Expected** **Output** as XML. 

| Authentication Credentials | Description |
| --- | --- |
| Login | This will present a Login screen to the user (not recommended for API) |
| Guest | A special Guest account can be enabled, and access to folders can be granted to this account. |
| SessionId/Named Session | The recommended approach for API calls. To learn more, see [Create Named Session](/version-10/docs/named-session). |
| Specify User Credentials | Defines the username and password of the user |

![](https://cdn.document360.io/6ef8bcc1-6489-4486-9ad1-83acff7e5df0/Images/Documentation/image-1749738298075.png)
11. Copy the Parameters under **Call via POST** into the desired REST Service software to set up a POST call. ![](https://cdn.document360.io/6ef8bcc1-6489-4486-9ad1-83acff7e5df0/Images/Documentation/image-1749738352696.png)
12. Navigate to the TEST tab, select POST, then click RUN to test the call. 

![](https://cdn.document360.io/6ef8bcc1-6489-4486-9ad1-83acff7e5df0/Images/Documentation/image-1749738468199.png)