Applying IronPDF License Key to Projects

January 19, 2022

Updated June 1, 2025

The license key is a long string that ends with the license support expiry date. Please ensure this is copied correctly.

IRONPDF-MYLICENSE-KEY-1EF01-EXPIRES.01.JAN.2050

Any additional spaces or characters in the license key string will result in the following error:

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

The most robust method of applying a license key is directly in your code, before the library is called.

// Set the license key for IronPDF before making any calls to the library.
IronPdf.License.LicenseKey = "IRONPDF-MYLICENSE-KEY-EXPIRES.01.JAN.2050";

// Set the license key for IronPDF before making any calls to the library.
IronPdf.License.LicenseKey = "IRONPDF-MYLICENSE-KEY-EXPIRES.01.JAN.2050";

' Set the license key for IronPDF before making any calls to the library.
IronPdf.License.LicenseKey = "IRONPDF-MYLICENSE-KEY-EXPIRES.01.JAN.2050"

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Please note

Starting from IronPdf version 2024.1.20 onwards, users are required to have at least a free trial license key in order to use the IronPDF library in their projects. Absence of a license key in the project will throw the LicensingException error noted above.

For more options, including web.config and appsettings.json, please see the following how-to page for more information: IronPDF License Keys