1. IronPDF
  2. Troubleshooting
  3. Apply a license key in IronPDF

Applying IronPDF License Key to Projects

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 below 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.

IronPdf.License.LicenseKey = "IRONPDF-MYLICENSE-KEY-EXPIRES.01.JAN.2050";
IronPdf.License.LicenseKey = "IRONPDF-MYLICENSE-KEY-EXPIRES.01.JAN.2050";
IronPdf.License.LicenseKey = "IRONPDF-MYLICENSE-KEY-EXPIRES.01.JAN.2050"
VB   C#

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 IronPDF library in their project. Absence of license key in the project will throw the error above.

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