Profile ASP.NET web app on Azure App Service on Windows

This article describes how to set up profiling of ASP.NET web app in a Windows container running on Azure App Service.

YourKit Connection Broker setup

We will use YourKit Connection Broker as a middleware, which helps to establish connection between profiler UI and the profiler agent running on the cloud.

This is a step-by-step instruction how to sign-up YourKit Connection Broker account. All preparations should not take more than 5 minutes. You need to create a security zone and access token to it.

In this example:

• The connection broker has https://cloud.yourkit.com address. The real broker address is the cloud region address of the security zone.
• The access token to the security zone is mytoken. The real token you have just created on the first YourKit Connection Broker setup step.

Download profiler to the container

Select your application in the Azure App Service portal. In the left navigation, select Console under Development Tools section.

We need the profiler agent to be available in a persistent location. Let's download and unpack it to the C:\home directory. To do this, type the following commands in the console.

cd /d C:\home
curl -fLOSs https://www.yourkit.com/dotnet-profiler/download/docker/YourKit-NetProfiler-2025.3-docker.zip
unzip -o YourKit-NetProfiler-2025.3-docker.zip

Enable profiling in the Azure portal

In the app's left menu, select Configuration > Application settings.

To be able to capture snapshots and analyze them after container restarts, we'll set a writeable and persistent snapshot directory C:\home\snapshots with the startup option dir.

To enable profiling we need to add the following settings. Make sure to enter correct agent path and broker settings.

Name	Value
YNP_STARTUP_OPTIONS	broker_url=https://cloud.yourkit.com,broker_token=mytoken,dir=C:\home\snapshots
Enable profiling of ASP.NET Core apps
CORECLR_ENABLE_PROFILING	1
CORECLR_PROFILER	{E5A4ADC4-C749-400D-B066-6AC8C1D3790A}
CORECLR_PROFILER_PATH_64	C:\home\YourKit-NetProfiler\bin\windows-x86-64\ynpagent.dll
CORECLR_PROFILER_PATH_32	C:\home\YourKit-NetProfiler\bin\windows-x86-32\ynpagent.dll
Enable profiling of ASP.NET Framework apps
COR_ENABLE_PROFILING	1
COR_PROFILER	{E5A4ADC4-C749-400D-B066-6AC8C1D3790A}
COR_PROFILER_PATH_64	C:\home\YourKit-NetProfiler\bin\windows-x86-64\ynpagent.dll
COR_PROFILER_PATH_32	C:\home\YourKit-NetProfiler\bin\windows-x86-32\ynpagent.dll

To add a new app setting, click New application setting. After new settings are saved application should restart with profiling enabled.

Connect to the profiled application from the UI

Use Profile remote application... action on Welcome screen or in Profile menu.

Choose the YourKit Connection Broker discovery method.

Provide broker URL and broker access token in the corresponding fields.

Created connection will appear in the Monitor Applications list on Welcome screen.

Open ASP.NET application in a browser to make sure .NET runtime is loaded. Profiled application will appear in the list, from which you can click on it to connect.

Stop profiling

To disable profiling, set CORECLR_ENABLE_PROFILING and COR_ENABLE_PROFILING application setting values to 0. Alternatively, remove all settings added on previous steps.