IronZip License Setup in web.config

Updated: July 21, 2026

This issue is known to affect IronZip versions released before 2024.3.3.

Please note: That version's published release notes don't itemize a Web.config/appSettings licensing fix specifically, so if you're on 2024.3.3 or later and still see this exception, the workaround below still applies.

Exception: Unhandled exception. IronSoftware.Exceptions.LicensingException: IronZip must be licensed for development.

Exception: Unhandled exception. IronSoftware.Exceptions.LicensingException: IronZip must be licensed for development.

SHELL

For older IronZIP versions, specifically those released before version 2024.3.3, there is a known licensing issue in:

ASP.NET projects
.NET Framework version >= 4.6.2

The key stored in a Web.config file will NOT be picked up and used by the product.

Workaround

To address this issue, it is recommended to retrieve the license key from the Web.config file using ConfigurationManager in the code, and then apply it to the License.LicenseKey property.

Example:

<configuration>
  ...
  <appSettings>
    <add key="IronZip.LicenseKey" value="IRONZIP.MYLICENSE.KEY.1EF01"/>
  </appSettings>
  ...
</configuration>

<configuration>
  ...
  <appSettings>
    <add key="IronZip.LicenseKey" value="IRONZIP.MYLICENSE.KEY.1EF01"/>
  </appSettings>
  ...
</configuration>

XML

With the XML file provided above, we can use ConfigurationManager to retrieve the license key value and pass it to the IronZip.License.LicenseKey property.

using System;
using System.Configuration;

class Program
{
    static void Main()
    {
        // Retrieve the license key from the web.config appSettings
        string licenseKey = ConfigurationManager.AppSettings["IronZip.LicenseKey"];

        // Apply the license key to IronZip
        IronZip.License.LicenseKey = licenseKey;

        // Verify that the license key is set properly
        Console.WriteLine("License key applied successfully.");
    }
}

using System;
using System.Configuration;

class Program
{
    static void Main()
    {
        // Retrieve the license key from the web.config appSettings
        string licenseKey = ConfigurationManager.AppSettings["IronZip.LicenseKey"];

        // Apply the license key to IronZip
        IronZip.License.LicenseKey = licenseKey;

        // Verify that the license key is set properly
        Console.WriteLine("License key applied successfully.");
    }
}

Imports System
Imports System.Configuration

Friend Class Program
	Shared Sub Main()
		' Retrieve the license key from the web.config appSettings
		Dim licenseKey As String = ConfigurationManager.AppSettings("IronZip.LicenseKey")

		' Apply the license key to IronZip
		IronZip.License.LicenseKey = licenseKey

		' Verify that the license key is set properly
		Console.WriteLine("License key applied successfully.")
	End Sub
End Class

Imports System
Imports System.Configuration

Friend Class Program
	Shared Sub Main()
		' Retrieve the license key from the web.config appSettings
		Dim licenseKey As String = ConfigurationManager.AppSettings("IronZip.LicenseKey")

		' Apply the license key to IronZip
		IronZip.License.LicenseKey = licenseKey

		' Verify that the license key is set properly
		Console.WriteLine("License key applied successfully.")
	End Sub
End Class

The using System.Configuration; directive allows access to configuration files, such as Web.config.
ConfigurationManager.AppSettings["IronZip.LicenseKey"] retrieves the license key stored in the appSettings section of Web.config.
IronZip.License.LicenseKey = licenseKey; assigns the retrieved key to the IronZIP library to avoid licensing exceptions.
The Console.WriteLine() statement provides feedback to the developer that the license key application process is completed successfully.

Curtis Chau

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Technical Writer

Curtis Chau holds a Bachelor’s degree in Computer Science (Carleton University) and specializes in front-end development with expertise in Node.js, TypeScript, JavaScript, and React. Passionate about crafting intuitive and aesthetically pleasing user interfaces, Curtis enjoys working with modern frameworks and creating well-structured, visually appealing manuals.

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