---
title: "Sending Composite Data through REST"
slug: "sending-complex-data-through-rest"
description: "Learn how to send Composite Data Types via the POST method using Rest Service Integration."
updated: 2026-06-30T18:19:21Z
published: 2026-06-30T18:19:21Z
canonical: "documentation.decisions.com/sending-complex-data-through-rest"
---

> ## 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.

# Sending Composite Data through REST

## Overview

This tutorial demonstrates how to send **Composite Data Types** via the **POST** method using **Rest Service Integration**.

---

## Define the Rest Service

Use the example to create a Rest Service Integration with the POST method. Then, add a custom Rest Header to the Service Integration. Finally, create a simple Flow to test sending the Composite Data Type with the custom Rest Header and deserialize the returned Data. 

1. Create a [REST Service](/version-10/docs/creating-a-rest-method)
2. From the newly created Rest Service Folder, navigate to **All > Add Method to Service**. ![](https://cdn.document360.io/6ef8bcc1-6489-4486-9ad1-83acff7e5df0/Images/Documentation/image-1781788441084.png)
3. In the resulting pop-up window, provide a **Name**, and define the **URL** .
4. Define the **HTTP Method** as **POST** and **Service Content-Type** as **JSON.**
5. Select **Specify Below (Use {} for variables)** from the **Request Body Format** dropdown. The Request Body is used to define the Composite Data Type between the two curly brackets. Define the **Request Body** as the following code snippet, then select **OK.**

```json
{
"namedsession": "{sessionID}", 
"datastring": "{stringinput}"
}
```

![](https://cdn.document360.io/6ef8bcc1-6489-4486-9ad1-83acff7e5df0/Images/Documentation/image-1781788413958.png)

---

## Design the Flow

1. Navigate to a **Designer Project** and **CREATE** a new Flow.
2. In the Toolbox expand **INTEGRATION > REST SERVICES > [NAME OF SERVICE]**.
3. Drag and drop the **Test** step into the workspace.
4. Navigate to the **Properties** panel and expand **Inputs**. Notice the two variables that were defined in the **Request Body** of the Method.![](https://cdn.document360.io/6ef8bcc1-6489-4486-9ad1-83acff7e5df0/Images/Documentation/image-1781788708897.png)

---

## Other Request Body Formats

1. Navigate to the previously created Rest Service Folder, **System > Integrations > External Services. Next, select** the Method, choose **Edit Method** in the action menu.![](https://cdn.document360.io/6ef8bcc1-6489-4486-9ad1-83acff7e5df0/Images/Documentation/image-1781788749442.png)
2. In the REST Service Method dialog, change the **Request Body Format** to **Serialize from Data Type**.
3. Under **Request Body Data Type**, search for and select **Account**.
4. Select **OK**.![](https://cdn.document360.io/6ef8bcc1-6489-4486-9ad1-83acff7e5df0/Images/Documentation/image-1781788795235.png)
5. Navigate back to the previously created Flow.
6. Select the same step used in the previous example and open the **Properties** panel. Notice that the **Inputs** changed to the **Account** data type. ![](https://cdn.document360.io/6ef8bcc1-6489-4486-9ad1-83acff7e5df0/Images/Documentation/image-1781788853971.png)