Setting Up Your Telerik UI for ASP.NET AJAX License Key
Starting with the 2025 Q1 release, the UI components from the Telerik UI for ASP.NET AJAX library require activation through a license key (trial or commercial).
This article describes how to download your personal license key and use it to activate the Telerik UI for ASP.NET AJAX components.
A missing or invalid license results in errors and warnings during build and run-time indicators such as watermarks and banners.
Setup your License Key
Due to the differences between Web Application Project and Web Site Project, the steps to activate the license will differ. One of the easiest ways to distinguish them is by checking if the project has a project file (.csproj/.vbproj) or not.
Web Application Projects> have a Project file.Web Site Projects> do not have a Project file.
For more details about the differences you can check out the following Microsoft documentation article: Web Application Projects versus Web Site Projects in Visual Studio.
Web Application
To download and install your Telerik license key file:
- Go to the License Keys page in your Telerik account.
- Click the Download License Key button.
- Save the
telerik-license.txtfile to your user profile directory%AppData%\Telerik\telerik-license.txt, for example,C:\Users\...\AppData\Roaming\Telerik\telerik-license.txt
This will make the license key available to all Telerik applications that you develop on your local machine. If you need to activate Telerik UI for ASP.NET AJAX only in a specific application, save the telerik-license.txt to the root folder of this project or solution.
Web Site
The license for Web Sites projects can be activated by adding a license Script key:
- Go to the License Keys page in your Telerik account.
- On the Telerik UI for ASP.NET AJAX row, click the
View keylink. - Select the language (
C# KEYorVB KEY) and click theCopy and closebutton to copy the Script Key to your clipboard. - Add a C#/VB Class file to the
App_Codedirectory of your project, e.g.App_Code\TelerikLicense.csand paste the Script Key from your clipboard.
To activate the license in other Web Site projects, repeat these steps.