How to Download Binary File (PDF, Image, ZIP) from URL in SSIS Data Flow using Web API Destination

hardik · January 1, 2026, 2:08pm

Introduction

A frequently asked question on community.zappysys.com is:

“I can download a file from a URL using the REST API Task in Control Flow, but how do I download the same file inside Data Flow ?”

This article explains the recommended and supported approach to download binary files (PDF, Image, ZIP, etc.) inside SSIS Data Flow using Web API Destination.

This pattern is especially useful when:

URLs are stored in a table or CSV file
Each row represents one file to download
Files must be downloaded dynamically and in bulk

The solution documented here is based on a real support case and follows the same style and best practices used in other ZappySys community articles.

Why REST API Task Is Not Enough

The REST API Task and Download File Task work only in Control Flow , which is ideal for:

Single or static downloads
One-time operations

However, Control Flow is not row-based .

If you need to:

Download files dynamically per row
Drive downloads from a table / CSV / query
Process hundreds or thousands of URLs

Then Data Flow is the correct choice.

Recommended Approach (Data Flow)

To download a file inside Data Flow:

Use Web API Destination
Enable Treat Response as Binary
Capture the binary response in an output column
Write the binary content to disk using FUN_FILE_WRITE_BINARY

This is the same approach recommended across multiple ZappySys community articles.

High-Level Design

Source (CSV / Table)

       ↓

Web API Destination (GET + Binary Response)

       ↓

Derived Column / Template Transform

       ↓

File written to disk

Step-by-Step Configuration

Step 1: Configure Source

Use any SSIS source that provides the download URL dynamically.

Typical columns:

FileUrl – URL to download (e.g., AWS S3 pre-signed URL)
FileName – Output file name (PDF, ZIP, etc.)
OutputFolder – Target folder path

Example: CSV Source

Step 2: Configure Web API Destination

Add Web API Destination and configure the following:

General Tab

HTTP Method: GET
Request URL: Map from FileUrl column
Treat Response as Binary (mandatory)

If Treat Response as Binary is not enabled, the downloaded file will be corrupted.

Step 3: Output from Web API Destination

Once configured, the component produces a binary output column (for example):

ResponseBinary

This column contains the raw file bytes returned by the HTTP endpoint.

Step 4: Write Binary Content to File

Add Template Transform and use the built-in function:

<<D:\demo1.pdf|~|<%ResponseText%>|~|True,FUN_FILE_WRITE_BINARY>>

This function writes the binary response directly to a physical file location.

Step 5: Validate Output

After execution:

Confirm the file exists in the target folder
Open the file (PDF / image / ZIP)
Verify that the file is not corrupted

Dynamic & Bulk Download Scenarios

This approach works seamlessly when:

URLs are stored in a database table
URLs are read from CSV / Excel
URLs are generated dynamically using expressions

Each input row results in one downloaded file.

Summary & Best Practices

Scenario	Recommended Component
Single / Static download	REST API Task / Download File Task
Row-based / Dynamic download	Web API Destination (Data Flow)

Key Takeaways

Always enable Treat Response as Binary
Use FUN_FILE_WRITE_BINARY to persist files
Data Flow is ideal for scalable and dynamic downloads