Telerik UI for ASP.NET AJAX 2025 Q1 License Key Build Error

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Licensing

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Accepted

answered on 13 Feb 2025, 08:20 AM

Thank you Aaron for the tip! It will go into the documentation.

I want to share yet another way to prevent the licensing warnings:

Go to the License Keys page in your Telerik account.
Click the Download License Key button.
Save the telerik-license.txt file to:

%AppData%\Telerik\telerik-license.txt, for example, C:\Users\...\AppData\Roaming\Telerik\telerik-license.txt

Additional directories where you can place the telerik-license.txt are:

C:\inetpub\wwwroot\telerik-license.txt
C:\inetpub\telerik-license.txt
C:\telerik-license.txt

If you are using Kendo UI, also place kendo-ui-license.txt in these directories.

This will make the license key available to all Telerik .NET apps you develop on your local machine.

Regards,
Rumen
Progress Telerik

Stay tuned by visiting our public roadmap and feedback portal pages! Or perhaps, if you are new to our Telerik family, check out our getting started resources!

Daniel

commented on 17 Feb 2025, 03:55 PM

Does this apply when deploying our application to a production environment or just for developer's local environment?

Rumen

commented on 17 Feb 2025, 04:11 PM

Hi Daniel,

The licensing mechanism for Telerik UI for ASP.NET AJAX applies primarily to the developer's local environment and is not required for deployment in a production environment. The license key is used to verify and activate the developer’s access during development, but it does not need to be present on the production server.

For more details, you can refer to the official Telerik documentation:

Let me know if you need further clarification!

gerry

commented on 24 Feb 2025, 03:07 PM

Just to clarify, to deploy to a production environment (e.g. cloud) we can still just do bin directory deployments and we don't need anything else?

Rumen

commented on 24 Feb 2025, 04:01 PM

Yes, for deploying to a production environment (including cloud), bin directory deployment is sufficient. You do not need to include the Telerik license key file on the production server.

The Telerik licensing mechanism is only required during development to validate access. Once your application is built and deployed, the assemblies in the bin directory will function as expected without needing any additional licensing steps.

John S.

commented on 10 Jun 2025, 05:01 PM

Rumen

'The Telerik licensing mechanism is only required during development to validate access.'

When I deploy to production I must include an App_Code/TelerikLicense.vb as well as a separate TelerikLicense.vb in the root site directory to cover the reporting license. This is for a web application using vb.net.

There seems to be a lot of contradictory wording and I find it overly complicated. I followed your advice here and was presented with a watermarked application with license warnings and report license warnings (I followed those directions as well)

I spent an hour or so of trial and error on a production application while users are being confused with these messages. I would think having a valid license installed on my dev machine would compile whatever is necessary into the build file. It also seems like placing my license on a clients server is not the best policy in the world.

Can you give me clear directions in a VB.NET web application what the configuration 'should' be. This is what the documentation says A says one thing and B says another and my experience none of it is correct. I have a Web Application but have to install as a Web Site.

Also, do I need a new license for service packs?

A

Setting Up Your License Key

Starting with Telerik UI for ASP.NET AJAX 2025 Q1 release, you must activate the UI components by providing a license key file. Previous versions do not require a license key.

To download and install your Telerik license key:

Go to the License Keys page in your Telerik account.
Click the Download License Key button.
Save the telerik-license.txt file to:
- %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 .NET apps that you develop on your local machine.

B

Web Applications without NuGet and Web Sites

Web Applications projects that do not use NuGet and Web Site projects require an assembly attribute, containing the License Key. Follow the steps below:

Go to the License Keys page in your Telerik account.
On the Telerik UI for ASP.NET AJAX row, click the View key link.
Select the language (C# KEY or VB KEY) and click the Copy and close button to copy the Script Key to your clipboard.
Adding the License Key script:
- Web Application: Paste the copied key to the Properties > AssemblyInfo
- Web Site: Add a C#/VB Class file to the App_Code directory of your project, e.g. App_Code\TelerikLicense.cs and paste the Script Key from your clipboard.

Rumen

commented on 29 May 2025, 11:59 AM

Hi Andres,

Thank you for sharing your experience - we're really sorry to hear that recent updates have been frustrating. We know how valuable your time is, and it's never our intention to cause disruption during upgrades.

Please know that we're doing our best to address all occurring issues related to licensing and upgrade with highest priority. We take all customer feedback seriously, and it's actively used to fix problems, improve our documentation, make it easier to follow, and enhance the Visual Studio Extensions and upgrade tools to simplify the overall process.

Your input plays an important role in helping us improve, and we're grateful you're taking the time to speak up. If you run into any specific blockers, we’d be glad to assist.

Thank you again for your patience and for being part of the Telerik community.

answered on 11 Jun 2025, 04:12 PM

Hi everyone,

To clear up the confusion:

If your project is a Web Application using the Telerik.Licensing NuGet package:
- Just download the telerik-license.txt file and place it in %AppData%\Telerik\ on your development machine.
- The license will be embedded automatically into the compiled assembly via MSBuild.
- You do not need to include the license file or key in production – it’s already embedded at build time.

If your project is a Web Application not using NuGet but referencing Telerik.Licensing.dll directly:
- You must manually embed the license by adding a TelerikLicense.cs (or .vb) file to your project, or placing the attribute in AssemblyInfo.cs / AssemblyInfo.vb.
- This file should contain:
```
[assembly: Telerik.Licensing.EvidenceAttribute("your-license-key-here")]
```
- It gets compiled into your application DLL.
- Once compiled, no license file is needed on the production server.

If your project is an ASP.NET Web Site project (the legacy type):
- These web site projects can’t embed license attributes into a compiled assembly due to technology limitations.
- You must include a TelerikLicense.cs or TelerikLicense.vb file in the App_Code folder.
- This file needs to be present both in development and on the production server, because the license is validated at runtime.

In summary:

NuGet Web App       → uses %AppData%\telerik-license.txt at build time → no file needed in production  
DLL-only Web App   → requires TelerikLicense.cs/vb or Properties > AssemblyInfo.cs/ My Project > AssemblyInfo.vb → compiles into assembly → no file needed in production  
Web Site Project      → requires TelerikLicense.cs/vb in App_Code → must be present in production (runtime check)

We’ll continue to improve the documentation to better reflect these nuances. Thanks again to everyone who shared their experience and helped clarify this!

Regards,
Rumen
Progress Telerik

Stay tuned by visiting our public roadmap and feedback portal pages! Or perhaps, if you are new to our Telerik family, check out our getting started resources!

John S.

commented on 11 Jun 2025, 05:28 PM

Thank you Rumen,

And when is it necessary to update the license on the production server?

Vasko

commented on 13 Jun 2025, 07:24 AM

Hello John,

In most cases, you don’t need to update the license on the production server, because the license is either embedded at build time (for Web Applications), or validated during runtime (for Web Sites).

However, there are a few situations where you might need to update the license on production:

If you’re using an ASP.NET Web Site project (not Web Application) — you must include the TelerikLicense.cs (or .vb) file in the App_Code folder on both development and production. That’s because license validation happens at runtime for Web Sites.
If your license has expired and you’re trying to deploy a build that uses a newer Telerik version than what your license allows, you’ll see a warning or watermark. In that case, you’ll need to renew the license and download a fresh key.
If you’re deploying from a CI/CD pipeline, make sure the correct license key is set as an environment variable or placed in the proper location so it's embedded during the build.

To summarize:

Web Application with NuGet or direct DLL reference: license is embedded at build time → no need to copy license to production.
ASP.NET Web Site: license file must be present on the server because validation happens at runtime.

For mroe information, please take a look at the Frequently Asked Questions article.

Regards,
Author nickname
Progress Telerik