---
title: "How to: Make a Multipart API Call in Unqork"
slug: "use-case-making-a-multipart-api-call-in-unqork"
description: "Learn how to make multipart API calls in Unqork, including configuring components for MIME types and Base64 encoding for seamless integration."
updated: 2026-01-20T18:03:21Z
published: 2026-01-20T20:38:53Z
canonical: "docs.unqork.io/use-case-making-a-multipart-api-call-in-unqork"
---

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

# How to: Make a Multipart API Call in Unqork

Making a **multipart API call** in Unqork requires a [Plug-In](/v1/docs/plug-in-component) component like other API calls, but you'll also use a [Calculator](/v1/docs/calculator-component) component to define the MIME Types (Multipurpose Internet Mail Extensions) included in your request. Let's look at a common example of sending a Base64 encoded PDF in a POST call.

> [!TIP]
> You do not need to use multipart API calls for Unqork services. This example shows the steps you’d follow once you’ve set up an integration that requires a multipart API call. Meaning, this guide is only an example and you cannot perform this call in Express View.

> [!NOTE]
> These instructions assume you have a new module open, saved, and with a title.

## Configuration

Select the tab that corresponds to your Unqork Designer experience:

**UDesigner**

### Configure the Hidden Components

The first two [Hidden](/v1/docs/hidden-component) components will store the PDF MIME Type and the Base64 encoding for the PDF. Later, you’ll set up a [Calculator](/v1/docs/calculator-component) component to combine them.

1. In the Module Builder, drag and drop the first **Hidden** component onto your canvas.
2. In the **Property ID** and **Label Text** fields, enter `base64OfFile`.
3. Click **Save Component**.
4. Drag and drop a second **Hidden** component onto your canvas, placing it below the first Hidden component.
5. In the **Property ID** and **Label Text** fields, enter `mimeType`.
6. In the **Default Value** field, enter `application/pdf`.

> [!NOTE]
> In this case, our MIME type is a PDF. You’ll replace `application/pdf` with whatever MIME type you’re using.
7. Click **Save Component**.

### Configure the Calculator Component

This [Calculator](/v1/docs/calculator-component) component combines the values from your first two Hidden components in the `encodedFileURI` you’ll add in the next step.

1. Drag and drop a **Calculator** component onto your canvas, placing it below your Hidden components.
2. In the **Property ID** and **Label Text** fields, enter `calcMimeType`.
3. In the **Inputs** table, enter the following:

| # | Source | Alias | Required |
| --- | --- | --- | --- |
| 1 | base64OfFile | pdf | ![](https://cdn.us.document360.io/15548f06-2fba-434c-b0c1-5df88317dbd7/Images/Documentation/Checked_Box(7).png?sv=2026-02-06&spr=https&st=2026-11-09T03%3A51%3A20Z&se=2026-11-09T04%3A51%3A20Z&sr=c&sp=r&sig=wmiUHh1Y4cpQ9Nxa9zkJh6i1c5yCCOYqGjhq6r7QfXg%3D) (checked) |
| 2 | mimeType | mime | ![](https://cdn.us.document360.io/15548f06-2fba-434c-b0c1-5df88317dbd7/Images/Documentation/Checked_Box(7).png?sv=2026-02-06&spr=https&st=2026-11-09T03%3A51%3A20Z&se=2026-11-09T04%3A51%3A20Z&sr=c&sp=r&sig=wmiUHh1Y4cpQ9Nxa9zkJh6i1c5yCCOYqGjhq6r7QfXg%3D) (checked) |
4. In the **Outputs** table, enter the following:

| # | Source | Formula |
| --- | --- | --- |
| 1 | encodeFileURI | =CONCATENATE('data:',mime,';base64,',pdf) |

![Calculator settings with Inputs and Outputs tables highlighted.](https://cdn.us.document360.io/15548f06-2fba-434c-b0c1-5df88317dbd7/Images/Documentation/MultiPartAPICall_calcMimeType(1).png?sv=2026-02-06&spr=https&st=2026-11-09T03%3A51%3A20Z&se=2026-11-09T04%3A51%3A20Z&sr=c&sp=r&sig=wmiUHh1Y4cpQ9Nxa9zkJh6i1c5yCCOYqGjhq6r7QfXg%3D)
5. Click **Save Component**.

### Configure the Hidden Component

The third [Hidden](/v1/docs/hidden-component) component in this configuration serves as the output for the [Calculator](/v1/docs/calculator-component) component.

1. Drag and drop a **Hidden** component onto your canvas, placing it below your Calculator component.
2. In the **Property ID** and **Label Text** fields, enter `encodedFileURI`.
3. Click **Save Component**.

### Configure the Plug-In Component

This [Plug-In](/v1/docs/plug-in-component) component handles the API call. Here, you'll specify that you're making a multipart API call. Again, these instructions assume that you've already set up an API in [Services Administration](/v1/docs/services-administration). In the following steps, you'll select that API from the **Services** drop-down.

1. Drag and drop a **Plug-In** component onto your canvas, placing it below your `encodedFileURI` **Hidden** component.
2. In the **Property ID** and **Canvas Label Text** fields, enter `pluginMultipartApiCall`.
3. From the **Internal Services** drop-down, select your API. Ensure the **Request Type** is set to **POST**.
4. Set **Make a Multipart API Call** to ![](https://cdn.us.document360.io/15548f06-2fba-434c-b0c1-5df88317dbd7/Images/Documentation/image(771).png?sv=2026-02-06&spr=https&st=2026-11-09T03%3A51%3A20Z&se=2026-11-09T04%3A51%3A20Z&sr=c&sp=r&sig=wmiUHh1Y4cpQ9Nxa9zkJh6i1c5yCCOYqGjhq6r7QfXg%3D) **(ON)**.

> [!NOTE]
> A box displays letting you enter an **Alternative Multipart Sub-Type**. If your API requires a type other than **multipart/form-data**, enter it here.
5. In the **Inputs** table, enter the following:

| Property ID | Mapping | Required |
| --- | --- | --- |
| encodedFileURI | file | ![](https://cdn.us.document360.io/15548f06-2fba-434c-b0c1-5df88317dbd7/Images/Documentation/Checked_Box(7).png?sv=2026-02-06&spr=https&st=2026-11-09T03%3A51%3A20Z&se=2026-11-09T04%3A51%3A20Z&sr=c&sp=r&sig=wmiUHh1Y4cpQ9Nxa9zkJh6i1c5yCCOYqGjhq6r7QfXg%3D) (checked) |

![Plug-In component settings with Request Type, Make a multipart API call and the Inputs table highlighted.](https://cdn.us.document360.io/15548f06-2fba-434c-b0c1-5df88317dbd7/Images/Documentation/MultiPartAPICall_pluginMultipartApiCall.png?sv=2026-02-06&spr=https&st=2026-11-09T03%3A51%3A20Z&se=2026-11-09T04%3A51%3A20Z&sr=c&sp=r&sig=wmiUHh1Y4cpQ9Nxa9zkJh6i1c5yCCOYqGjhq6r7QfXg%3D)
6. Click **Save Component**.

### Configure the Button Component

The [Button](/v1/docs/how-to-guide-button-component) component trigger your [Plug-In](/v1/docs/plug-in-component) component when clicked, ultimately executing the API call.

1. Drag and drop a **Button** component onto your canvas, placing it below your Plug-In component.
2. In the **Property ID** field, enter `btnsubmitMultipartCall`.
3. In the **Label Text** field, enter `Submit Multipart Call`.
4. From the **Action Type** drop-down, select **Event**.
5. From the **On Click** drop-down, select **pluginMultipartApiCall**.

![Button component settings with Action Type and On Click fields highlighted.](https://cdn.us.document360.io/15548f06-2fba-434c-b0c1-5df88317dbd7/Images/Documentation/MakeMultiPartAPICall_btnsubmitMultipartCall.png?sv=2026-02-06&spr=https&st=2026-11-09T03%3A51%3A20Z&se=2026-11-09T04%3A51%3A20Z&sr=c&sp=r&sig=wmiUHh1Y4cpQ9Nxa9zkJh6i1c5yCCOYqGjhq6r7QfXg%3D)
6. Click **Save Component**.
7. **Save** your module.

**Classic Designer**

### Configure the Hidden Components

The first two [Hidden](/v1/docs/hidden-component) components will store the PDF MIME Type and the Base64 encoding for the PDF. Later, you’ll set up a [Calculator](/v1/docs/calculator-component) component to combine them.

1. In the Module Builder, drag and drop the first **Hidden** component onto your canvas.
2. In the **Property ID** and **Label Text** fields, enter `base64OfFile`.
3. Click **Save**.
4. Drag and drop a second **Hidden** component onto your canvas, placing it below the first Hidden component.
5. In the **Property ID** and **Label Text** fields, enter `mimeType`.
6. In the **Default Value** field, enter `application/pdf`.

> [!NOTE]
> In this case, our MIME type is a PDF. You’ll replace `application/pdf` with whatever MIME type you’re using.
7. Click **Save**.

### Configure the Calculator Component

This [Calculator](/v1/docs/calculator-component) component combines the values from your first two Hidden components in the `encodedFileURI` you’ll add in the next step.

1. Drag and drop a **Calculator** component onto your canvas, placing it below your Hidden components.
2. In the **Property ID** and **Label Text** fields, enter `calcMimeType`.
3. In the **Inputs** table, enter the following:

| # | Property ID | Alias | Required |
| --- | --- | --- | --- |
| 1 | base64OfFile | pdf | ![](https://cdn.us.document360.io/15548f06-2fba-434c-b0c1-5df88317dbd7/Images/Documentation/Checked_Box(7).png?sv=2026-02-06&spr=https&st=2026-11-09T03%3A51%3A20Z&se=2026-11-09T04%3A51%3A20Z&sr=c&sp=r&sig=wmiUHh1Y4cpQ9Nxa9zkJh6i1c5yCCOYqGjhq6r7QfXg%3D) (checked) |
| 2 | mimeType | mime | ![](https://cdn.us.document360.io/15548f06-2fba-434c-b0c1-5df88317dbd7/Images/Documentation/Checked_Box(7).png?sv=2026-02-06&spr=https&st=2026-11-09T03%3A51%3A20Z&se=2026-11-09T04%3A51%3A20Z&sr=c&sp=r&sig=wmiUHh1Y4cpQ9Nxa9zkJh6i1c5yCCOYqGjhq6r7QfXg%3D) (checked) |
4. In the **Outputs** table, enter the following:

| # | Property ID | Formula |
| --- | --- | --- |
| 1 | encodeFileURI | =CONCATENATE('data:',mime,';base64,',pdf) |

![Calculator component settings with Inputs and Outputs tables highlighted.](https://cdn.us.document360.io/15548f06-2fba-434c-b0c1-5df88317dbd7/Images/Documentation/MultiPartAPICall_calcMIMEtypeClassic.png?sv=2026-02-06&spr=https&st=2026-11-09T03%3A51%3A20Z&se=2026-11-09T04%3A51%3A20Z&sr=c&sp=r&sig=wmiUHh1Y4cpQ9Nxa9zkJh6i1c5yCCOYqGjhq6r7QfXg%3D)
5. Click **Save & Close**.

### Configure the Hidden Component

The third [Hidden](/v1/docs/hidden-component) component in this configuration serves as the output for the [Calculator](/v1/docs/calculator-component) component.

1. Drag and drop a **Hidden** component onto your canvas, placing it below your Calculator component.
2. In the **Property ID** and **Label Text** fields, enter `encodedFileURI`.
3. Click **Save**.

### Configure the Plug-In Component

This [Plug-In](/v1/docs/plug-in-component) component handles the API call. Here, you'll specify that you're making a multipart API call. Again, these instructions assume that you've already set up an API in [Services Administration](/v1/docs/services-administration). In the following steps, you'll select that API from the **Services** drop-down.

1. Drag and drop a **Plug-In** component onto your canvas, placing it below your `encodedFileURI` **Hidden** component.
2. In the **Property ID** and **Canvas Label Text** fields, enter `pluginMultipartApiCall`.
3. From the **Internal Services** drop-down, select your API. The Data Source URL automatically populates.
4. Set the **Request Type** as **POST**.
5. Set **Make a Multipart API Call** to ![](https://cdn.us.document360.io/15548f06-2fba-434c-b0c1-5df88317dbd7/Images/Documentation/image(771).png?sv=2026-02-06&spr=https&st=2026-11-09T03%3A51%3A20Z&se=2026-11-09T04%3A51%3A20Z&sr=c&sp=r&sig=wmiUHh1Y4cpQ9Nxa9zkJh6i1c5yCCOYqGjhq6r7QfXg%3D) **(ON)**.

> [!NOTE]
> A box appears letting you enter an **Alternative Multipart Sub-Type**. If your API requires a type other than **multipart/form-data**, enter it here.
6. In the **Inputs** table, enter the following:

| Property ID | Mapping | Required |
| --- | --- | --- |
| encodedFileURI | file | ![](https://cdn.us.document360.io/15548f06-2fba-434c-b0c1-5df88317dbd7/Images/Documentation/Checked_Box(7).png?sv=2026-02-06&spr=https&st=2026-11-09T03%3A51%3A20Z&se=2026-11-09T04%3A51%3A20Z&sr=c&sp=r&sig=wmiUHh1Y4cpQ9Nxa9zkJh6i1c5yCCOYqGjhq6r7QfXg%3D) (checked) |

![Plug-in component settings with settings highlighted.](https://cdn.us.document360.io/15548f06-2fba-434c-b0c1-5df88317dbd7/Images/Documentation/MultiPartAPICall_pluginMultipartApiCallClassic2.png?sv=2026-02-06&spr=https&st=2026-11-09T03%3A51%3A20Z&se=2026-11-09T04%3A51%3A20Z&sr=c&sp=r&sig=wmiUHh1Y4cpQ9Nxa9zkJh6i1c5yCCOYqGjhq6r7QfXg%3D)

![Plug-in component settings with Inputs table and Trigger Type highlighted.](https://cdn.us.document360.io/15548f06-2fba-434c-b0c1-5df88317dbd7/Images/Documentation/image-1768413721161.png?sv=2026-02-06&spr=https&st=2026-11-09T03%3A51%3A20Z&se=2026-11-09T04%3A51%3A20Z&sr=c&sp=r&sig=wmiUHh1Y4cpQ9Nxa9zkJh6i1c5yCCOYqGjhq6r7QfXg%3D)
7. Click **Save**.

### Configure the Button Component

The [Button](/v1/docs/how-to-guide-button-component) component triggers your [Plug-In](/v1/docs/plug-in-component) component when clicked, ultimately executing the API call.

1. Drag and drop a **Button** component onto your canvas, placing it below your Plug-In component.
2. In the **Property ID** field, enter `btnsubmitMultipartCall`.
3. In the **Label Text** field, enter `Submit Multipart Call`.
4. Setthe **Action Type** as **Event**.
5. From the **On Click** drop-down, select **pluginMultipartApiCall**.

![Button component settings with Action Type and On Click highlighted.](https://cdn.us.document360.io/15548f06-2fba-434c-b0c1-5df88317dbd7/Images/Documentation/MultiPartAPICall_btnsubmitMultipartApiCallClassic.png?sv=2026-02-06&spr=https&st=2026-11-09T03%3A51%3A20Z&se=2026-11-09T04%3A51%3A20Z&sr=c&sp=r&sig=wmiUHh1Y4cpQ9Nxa9zkJh6i1c5yCCOYqGjhq6r7QfXg%3D)
6. Click **Save & Close**.
7. **Save** your module.

APIs (application programming interfaces) are a set of protocols and definitions developers use to build and integrate application software. APIs act as the connective tissue between products and services.

Base64 is an encoding and decoding technique used to convert binary data to an ASCII (American Standard for Information Interchange) text format.

PDF (Portable Document Format) is a file format that allows users to share and print documents without modifying them.

The HTTP POST method is used to send data to a server to create or update a resource, typically including the data in the body of the request.

Express View is how your end-user views your application. Express View also lets you preview your applications to test your configuration and view the styling. This is also the view your end-users will see when interacting with your application. After configuring a module, click Preview in the Module Builder to interact with the module in Express View.

A Property ID is the unique field ID used by Unqork to track and link components in your module.

Label Text conveys what the input component is and what information it displays. Enter the purpose of the corresponding component or field.

Enter inputs components and actions you want the component to perform..

Enter outputs components and actions you want the component to perform.

Canvas Label Text indicates the purpose of the corresponding field or component. For non-input components, the Canvas Label Text isn't end-user facing, and only appears in the .