Application Insights for ASP.NET and ASP.NET Core applications

1. Open Visual Studio.
2. Select Create a new project.
3. Choose ASP.NET Web Application (.NET Framework) with C# and select Next.
4. Enter a Project name, then select Create.
5. Choose MVC, then select Create.

1. Open Visual Studio.
2. Select Create a new project.
3. Choose ASP.NET Core Web App (Razor Pages) with C# and select Next.
4. Enter a Project name, then select Create.
5. Choose a Framework (LTS or STS), then select Create.

From within your ASP.NET web app project in Visual Studio:

1. Select Project > Add Application Insights Telemetry > Application Insights Sdk (local) > Next > Finish > Close.

2. Open the ApplicationInsights.config file.

3. Before the closing </ApplicationInsights> tag, add a line that contains the connection string for your Application Insights resource. Find your connection string on the overview pane of the newly created Application Insights resource.

   <ConnectionString>Copy connection string from Application Insights Resource Overview</ConnectionString>
   

4. Select Project > Manage NuGet Packages > Updates. Then update each Microsoft.ApplicationInsights NuGet package to the latest stable release.

5. Run your application by selecting IIS Express. A basic ASP.NET app opens. As you browse through the pages on the site, telemetry is sent to Application Insights.

From within your ASP.NET web app project in Visual Studio:

1. Go to Project > Add Application Insights Telemetry.

2. Select Azure Application Insights > Next.

3. Choose your subscription and Application Insights instance. Or you can create a new instance with Create new. Select Next.

4. Add or confirm your Application Insights connection string. It should be prepopulated based on your selection in the previous step. Select Finish.

5. After you add Application Insights to your project, check to confirm that you're using the latest stable release of the SDK. Go to Project > Manage NuGet Packages > Microsoft.ApplicationInsights.AspNetCore. If you need to, select Update.

   

1. Add the following NuGet packages and their dependencies to your project:

   • Microsoft.ApplicationInsights.WindowsServer
   • Microsoft.ApplicationInsights.Web
   • Microsoft.AspNet.TelemetryCorrelation

2. In some cases, the ApplicationInsights.config file is created for you automatically. If the file is already present, skip to step 4.

   Create it yourself if it's missing. In the root directory of an ASP.NET application, create a new file called ApplicationInsights.config.

3. Copy the following XML configuration into your newly created file:

   
   
   Expand to view the configuration

   <?xml version="1.0" encoding="utf-8"?>
   <ApplicationInsights xmlns="http://schemas.microsoft.com/ApplicationInsights/2013/Settings">
     <TelemetryInitializers>
       <Add Type="Microsoft.ApplicationInsights.DependencyCollector.HttpDependenciesParsingTelemetryInitializer, Microsoft.AI.DependencyCollector" />
       <Add Type="Microsoft.ApplicationInsights.WindowsServer.AzureRoleEnvironmentTelemetryInitializer, Microsoft.AI.WindowsServer" />
       <Add Type="Microsoft.ApplicationInsights.WindowsServer.BuildInfoConfigComponentVersionTelemetryInitializer, Microsoft.AI.WindowsServer" />
       <Add Type="Microsoft.ApplicationInsights.Web.WebTestTelemetryInitializer, Microsoft.AI.Web" />
       <Add Type="Microsoft.ApplicationInsights.Web.SyntheticUserAgentTelemetryInitializer, Microsoft.AI.Web">
         <!-- Extended list of bots:
               search|spider|crawl|Bot|Monitor|BrowserMob|BingPreview|PagePeeker|WebThumb|URL2PNG|ZooShot|GomezA|Google SketchUp|Read Later|KTXN|KHTE|Keynote|Pingdom|AlwaysOn|zao|borg|oegp|silk|Xenu|zeal|NING|htdig|lycos|slurp|teoma|voila|yahoo|Sogou|CiBra|Nutch|Java|JNLP|Daumoa|Genieo|ichiro|larbin|pompos|Scrapy|snappy|speedy|vortex|favicon|indexer|Riddler|scooter|scraper|scrubby|WhatWeb|WinHTTP|voyager|archiver|Icarus6j|mogimogi|Netvibes|altavista|charlotte|findlinks|Retreiver|TLSProber|WordPress|wsr-agent|http client|Python-urllib|AppEngine-Google|semanticdiscovery|facebookexternalhit|web/snippet|Google-HTTP-Java-Client-->
         <Filters>search|spider|crawl|Bot|Monitor|AlwaysOn</Filters>
       </Add>
       <Add Type="Microsoft.ApplicationInsights.Web.ClientIpHeaderTelemetryInitializer, Microsoft.AI.Web" />
       <Add Type="Microsoft.ApplicationInsights.Web.AzureAppServiceRoleNameFromHostNameHeaderInitializer, Microsoft.AI.Web" />
       <Add Type="Microsoft.ApplicationInsights.Web.OperationNameTelemetryInitializer, Microsoft.AI.Web" />
       <Add Type="Microsoft.ApplicationInsights.Web.OperationCorrelationTelemetryInitializer, Microsoft.AI.Web" />
       <Add Type="Microsoft.ApplicationInsights.Web.UserTelemetryInitializer, Microsoft.AI.Web" />
       <Add Type="Microsoft.ApplicationInsights.Web.AuthenticatedUserIdTelemetryInitializer, Microsoft.AI.Web" />
       <Add Type="Microsoft.ApplicationInsights.Web.AccountIdTelemetryInitializer, Microsoft.AI.Web" />
       <Add Type="Microsoft.ApplicationInsights.Web.SessionTelemetryInitializer, Microsoft.AI.Web" />
     </TelemetryInitializers>
     <TelemetryModules>
       <Add Type="Microsoft.ApplicationInsights.DependencyCollector.DependencyTrackingTelemetryModule, Microsoft.AI.DependencyCollector">
         <ExcludeComponentCorrelationHttpHeadersOnDomains>
           <!-- 
           Requests to the following hostnames will not be modified by adding correlation headers.
           Add entries here to exclude additional hostnames.
           NOTE: this configuration will be lost upon NuGet upgrade.
           -->
           <Add>core.windows.net</Add>
           <Add>core.chinacloudapi.cn</Add>
           <Add>core.cloudapi.de</Add>
           <Add>core.usgovcloudapi.net</Add>
         </ExcludeComponentCorrelationHttpHeadersOnDomains>
         <IncludeDiagnosticSourceActivities>
           <Add>Microsoft.Azure.EventHubs</Add>
           <Add>Azure.Messaging.ServiceBus</Add>
         </IncludeDiagnosticSourceActivities>
       </Add>
       <Add Type="Microsoft.ApplicationInsights.Extensibility.PerfCounterCollector.PerformanceCollectorModule, Microsoft.AI.PerfCounterCollector">
         <!--
         Use the following syntax here to collect additional performance counters:
   
         <Counters>
           <Add PerformanceCounter="\Process(??APP_WIN32_PROC??)\Handle Count" ReportAs="Process handle count" />
           ...
         </Counters>
   
         PerformanceCounter must be either \CategoryName(InstanceName)\CounterName or \CategoryName\CounterName
   
         NOTE: performance counters configuration will be lost upon NuGet upgrade.
   
         The following placeholders are supported as InstanceName:
           ??APP_WIN32_PROC?? - instance name of the application process for Win32 counters.
           ??APP_W3SVC_PROC?? - instance name of the application IIS worker process for IIS/ASP.NET counters.
           ??APP_CLR_PROC?? - instance name of the application CLR process for .NET counters.
         -->
       </Add>
       <Add Type="Microsoft.ApplicationInsights.Extensibility.PerfCounterCollector.QuickPulse.QuickPulseTelemetryModule, Microsoft.AI.PerfCounterCollector" />
       <Add Type="Microsoft.ApplicationInsights.WindowsServer.AppServicesHeartbeatTelemetryModule, Microsoft.AI.WindowsServer" />
       <Add Type="Microsoft.ApplicationInsights.WindowsServer.AzureInstanceMetadataTelemetryModule, Microsoft.AI.WindowsServer">
         <!--
         Remove individual fields collected here by adding them to the ApplicationInsighs.HeartbeatProvider
         with the following syntax:
   
         <Add Type="Microsoft.ApplicationInsights.Extensibility.Implementation.Tracing.DiagnosticsTelemetryModule, Microsoft.ApplicationInsights">
           <ExcludedHeartbeatProperties>
             <Add>osType</Add>
             <Add>location</Add>
             <Add>name</Add>
             <Add>offer</Add>
             <Add>platformFaultDomain</Add>
             <Add>platformUpdateDomain</Add>
             <Add>publisher</Add>
             <Add>sku</Add>
             <Add>version</Add>
             <Add>vmId</Add>
             <Add>vmSize</Add>
             <Add>subscriptionId</Add>
             <Add>resourceGroupName</Add>
             <Add>placementGroupId</Add>
             <Add>tags</Add>
             <Add>vmScaleSetName</Add>
           </ExcludedHeartbeatProperties>
         </Add>
   
         NOTE: exclusions will be lost upon upgrade.
         -->
       </Add>
       <Add Type="Microsoft.ApplicationInsights.WindowsServer.DeveloperModeWithDebuggerAttachedTelemetryModule, Microsoft.AI.WindowsServer" />
       <Add Type="Microsoft.ApplicationInsights.WindowsServer.UnhandledExceptionTelemetryModule, Microsoft.AI.WindowsServer" />
       <Add Type="Microsoft.ApplicationInsights.WindowsServer.UnobservedExceptionTelemetryModule, Microsoft.AI.WindowsServer">
         <!--</Add>
       <Add Type="Microsoft.ApplicationInsights.WindowsServer.FirstChanceExceptionStatisticsTelemetryModule, Microsoft.AI.WindowsServer">-->
       </Add>
       <Add Type="Microsoft.ApplicationInsights.Web.RequestTrackingTelemetryModule, Microsoft.AI.Web">
         <Handlers>
           <!-- 
           Add entries here to filter out additional handlers:
   
           NOTE: handler configuration will be lost upon NuGet upgrade.
           -->
           <Add>Microsoft.VisualStudio.Web.PageInspector.Runtime.Tracing.RequestDataHttpHandler</Add>
           <Add>System.Web.StaticFileHandler</Add>
           <Add>System.Web.Handlers.AssemblyResourceLoader</Add>
           <Add>System.Web.Optimization.BundleHandler</Add>
           <Add>System.Web.Script.Services.ScriptHandlerFactory</Add>
           <Add>System.Web.Handlers.TraceHandler</Add>
           <Add>System.Web.Services.Discovery.DiscoveryRequestHandler</Add>
           <Add>System.Web.HttpDebugHandler</Add>
         </Handlers>
       </Add>
       <Add Type="Microsoft.ApplicationInsights.Web.ExceptionTrackingTelemetryModule, Microsoft.AI.Web" />
       <Add Type="Microsoft.ApplicationInsights.Web.AspNetDiagnosticTelemetryModule, Microsoft.AI.Web" />
     </TelemetryModules>
     <ApplicationIdProvider Type="Microsoft.ApplicationInsights.Extensibility.Implementation.ApplicationId.ApplicationInsightsApplicationIdProvider, Microsoft.ApplicationInsights" />
     <TelemetrySinks>
       <Add Name="default">
         <TelemetryProcessors>
           <Add Type="Microsoft.ApplicationInsights.Extensibility.PerfCounterCollector.QuickPulse.QuickPulseTelemetryProcessor, Microsoft.AI.PerfCounterCollector" />
           <Add Type="Microsoft.ApplicationInsights.Extensibility.AutocollectedMetricsExtractor, Microsoft.ApplicationInsights" />
           <Add Type="Microsoft.ApplicationInsights.WindowsServer.TelemetryChannel.AdaptiveSamplingTelemetryProcessor, Microsoft.AI.ServerTelemetryChannel">
             <MaxTelemetryItemsPerSecond>5</MaxTelemetryItemsPerSecond>
             <ExcludedTypes>Event</ExcludedTypes>
           </Add>
           <Add Type="Microsoft.ApplicationInsights.WindowsServer.TelemetryChannel.AdaptiveSamplingTelemetryProcessor, Microsoft.AI.ServerTelemetryChannel">
             <MaxTelemetryItemsPerSecond>5</MaxTelemetryItemsPerSecond>
             <IncludedTypes>Event</IncludedTypes>
           </Add>
           <!--
             Adjust the include and exclude examples to specify the desired semicolon-delimited types. (Dependency, Event, Exception, PageView, Request, Trace)
           -->
         </TelemetryProcessors>
         <TelemetryChannel Type="Microsoft.ApplicationInsights.WindowsServer.TelemetryChannel.ServerTelemetryChannel, Microsoft.AI.ServerTelemetryChannel" />
       </Add>
     </TelemetrySinks>
     <!-- 
       Learn more about Application Insights configuration with ApplicationInsights.config here:
       http://go.microsoft.com/fwlink/?LinkID=513840
     -->
     <ConnectionString>Copy the connection string from your Application Insights resource</ConnectionString>
   </ApplicationInsights>
   

4. Add the connection string, which can be done in two ways:

   • (Recommended) Set the connection string in configuration.

     Before the closing </ApplicationInsights> tag in ApplicationInsights.config, add the connection string for your Application Insights resource. You can find your connection string on the overview pane of the newly created Application Insights resource.

     <ConnectionString>Copy the connection string from your Application Insights resource</ConnectionString>
     

   • Set the connection string in code.

     Provide a connection string in your program.cs class.

     var configuration = new TelemetryConfiguration
     {
         ConnectionString = "Copy the connection string from your Application Insights resource"
     };
     

5. At the same level of your project as the ApplicationInsights.config file, create a folder called ErrorHandler with a new C# file called AiHandleErrorAttribute.cs. The contents of the file look like this:

   using System;
   using System.Web.Mvc;
   using Microsoft.ApplicationInsights;
   
   namespace WebApplication10.ErrorHandler //namespace will vary based on your project name
   {
       [AttributeUsage(AttributeTargets.Class | AttributeTargets.Method, Inherited = true, AllowMultiple = true)] 
       public class AiHandleErrorAttribute : HandleErrorAttribute
       {
           public override void OnException(ExceptionContext filterContext)
           {
               if (filterContext != null && filterContext.HttpContext != null && filterContext.Exception != null)
               {
                   //If customError is Off, then AI HTTPModule will report the exception
                   if (filterContext.HttpContext.IsCustomErrorEnabled)
                   {   
                       var ai = new TelemetryClient();
                       ai.TrackException(filterContext.Exception);
                   } 
               }
               base.OnException(filterContext);
           }
       }
   }
   

6. In the App_Start folder, open the FilterConfig.cs file and change it to match the sample:

   using System.Web;
   using System.Web.Mvc;
   
   namespace WebApplication10 //Namespace will vary based on project name
   {
       public class FilterConfig
       {
           public static void RegisterGlobalFilters(GlobalFilterCollection filters)
           {
               filters.Add(new ErrorHandler.AiHandleErrorAttribute());
           }
       }
   }
   

7. If Web.config is already updated, skip this step. Otherwise, update the file as follows:

   
   
   Expand to view the configuration

   <?xml version="1.0" encoding="utf-8"?>
   <!--
     For more information on how to configure your ASP.NET application, please visit
     https://go.microsoft.com/fwlink/?LinkId=301880
     -->
   <configuration>
     <appSettings>
       <add key="webpages:Version" value="3.0.0.0" />
       <add key="webpages:Enabled" value="false" />
       <add key="ClientValidationEnabled" value="true" />
       <add key="UnobtrusiveJavaScriptEnabled" value="true" />
     </appSettings>
     <system.web>
       <compilation debug="true" targetFramework="4.7.2" />
       <httpRuntime targetFramework="4.7.2" />
       <!-- Code added for Application Insights start -->
       <httpModules>
         <add name="TelemetryCorrelationHttpModule" type="Microsoft.AspNet.TelemetryCorrelation.TelemetryCorrelationHttpModule, Microsoft.AspNet.TelemetryCorrelation" />
         <add name="ApplicationInsightsWebTracking" type="Microsoft.ApplicationInsights.Web.ApplicationInsightsHttpModule, Microsoft.AI.Web" />
       </httpModules>
       <!-- Code added for Application Insights end -->
     </system.web>
     <runtime>
       <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
         <dependentAssembly>
           <assemblyIdentity name="Antlr3.Runtime" publicKeyToken="eb42632606e9261f" />
           <bindingRedirect oldVersion="0.0.0.0-3.5.0.2" newVersion="3.5.0.2" />
         </dependentAssembly>
         <dependentAssembly>
           <assemblyIdentity name="Newtonsoft.Json" publicKeyToken="30ad4fe6b2a6aeed" />
           <bindingRedirect oldVersion="0.0.0.0-12.0.0.0" newVersion="12.0.0.0" />
         </dependentAssembly>
         <dependentAssembly>
           <assemblyIdentity name="System.Web.Optimization" publicKeyToken="31bf3856ad364e35" />
           <bindingRedirect oldVersion="1.0.0.0-1.1.0.0" newVersion="1.1.0.0" />
         </dependentAssembly>
         <dependentAssembly>
           <assemblyIdentity name="WebGrease" publicKeyToken="31bf3856ad364e35" />
           <bindingRedirect oldVersion="0.0.0.0-1.6.5135.21930" newVersion="1.6.5135.21930" />
         </dependentAssembly>
         <dependentAssembly>
           <assemblyIdentity name="System.Web.Helpers" publicKeyToken="31bf3856ad364e35" />
           <bindingRedirect oldVersion="1.0.0.0-3.0.0.0" newVersion="3.0.0.0" />
         </dependentAssembly>
         <dependentAssembly>
           <assemblyIdentity name="System.Web.WebPages" publicKeyToken="31bf3856ad364e35" />
           <bindingRedirect oldVersion="1.0.0.0-3.0.0.0" newVersion="3.0.0.0" />
         </dependentAssembly>
         <dependentAssembly>
           <assemblyIdentity name="System.Web.Mvc" publicKeyToken="31bf3856ad364e35" />
           <bindingRedirect oldVersion="1.0.0.0-5.2.7.0" newVersion="5.2.7.0" />
         </dependentAssembly>
         <!-- Code added for Application Insights start -->
         <dependentAssembly>
           <assemblyIdentity name="System.Memory" publicKeyToken="cc7b13ffcd2ddd51" culture="neutral" />
           <bindingRedirect oldVersion="0.0.0.0-4.0.1.1" newVersion="4.0.1.1" />
         </dependentAssembly>
         <!-- Code added for Application Insights end -->
       </assemblyBinding>
     </runtime>
     <system.codedom>
       <compilers>
         <compiler language="c#;cs;csharp" extension=".cs" type="Microsoft.CodeDom.Providers.DotNetCompilerPlatform.CSharpCodeProvider, Microsoft.CodeDom.Providers.DotNetCompilerPlatform, Version=2.0.1.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" warningLevel="4" compilerOptions="/langversion:default /nowarn:1659;1699;1701" />
         <compiler language="vb;vbs;visualbasic;vbscript" extension=".vb" type="Microsoft.CodeDom.Providers.DotNetCompilerPlatform.VBCodeProvider, Microsoft.CodeDom.Providers.DotNetCompilerPlatform, Version=2.0.1.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" warningLevel="4" compilerOptions="/langversion:default /nowarn:41008 /define:_MYTYPE=\&quot;Web\&quot; /optionInfer+" />
       </compilers>
     </system.codedom>
     <system.webServer>
       <validation validateIntegratedModeConfiguration="false" />
       <!-- Code added for Application Insights start -->
       <modules>
         <remove name="TelemetryCorrelationHttpModule" />
         <add name="TelemetryCorrelationHttpModule" type="Microsoft.AspNet.TelemetryCorrelation.TelemetryCorrelationHttpModule, Microsoft.AspNet.TelemetryCorrelation" preCondition="managedHandler" />
         <remove name="ApplicationInsightsWebTracking" />
         <add name="ApplicationInsightsWebTracking" type="Microsoft.ApplicationInsights.Web.ApplicationInsightsHttpModule, Microsoft.AI.Web" preCondition="managedHandler" />
       </modules>
       <!-- Code added for Application Insights end -->
     </system.webServer>
   </configuration>
   

At this point, you successfully configured server-side application monitoring. If you run your web app, you see telemetry begin to appear in Application Insights.

1. Install the Application Insights SDK NuGet package for ASP.NET Core.

   We recommend that you always use the latest stable version. Find full release notes for the SDK on the open-source GitHub repo.

   The following code sample shows the changes to add to your project's .csproj file:

   <ItemGroup>
       <PackageReference Include="Microsoft.ApplicationInsights.AspNetCore" Version="2.21.0" />
   </ItemGroup>
   

2. Add AddApplicationInsightsTelemetry() to your program.cs class.

   Add builder.Services.AddApplicationInsightsTelemetry(); after the WebApplication.CreateBuilder() method, as in this example:

   // This method gets called by the runtime. Use this method to add services to the container.
   var builder = WebApplication.CreateBuilder(args);
   
   // The following line enables Application Insights telemetry collection.
   builder.Services.AddApplicationInsightsTelemetry();
   
   // This code adds other services for your application.
   builder.Services.AddMvc();
   
   var app = builder.Build();
   

3. Add the connection string, which can be done in three ways:

   • (Recommended) Set the connection string in configuration.

     Set the connection string in appsettings.json and make sure the configuration file is copied to the application root folder during publishing.

     {
         "Logging": {
             "LogLevel": {
                 "Default": "Information",
                 "Microsoft.AspNetCore": "Warning"
             }
         },
         "AllowedHosts": "*",
         "ApplicationInsights": {
             "ConnectionString": "InstrumentationKey=00000000-0000-0000-0000-000000000000"
         }
     }
     

   • Set the connection string in the APPLICATIONINSIGHTS_CONNECTION_STRING environment variable or ApplicationInsights:ConnectionString in the JSON configuration file.

     For example:

     • SET ApplicationInsights:ConnectionString = <Copy connection string from Application Insights Resource Overview>
     • SET APPLICATIONINSIGHTS_CONNECTION_STRING = <Copy connection string from Application Insights Resource Overview>
     • Typically, APPLICATIONINSIGHTS_CONNECTION_STRING is used in Web Apps. It can also be used in all places where this SDK is supported.

     Note

     A connection string specified in code wins over the environment variable APPLICATIONINSIGHTS_CONNECTION_STRING, which wins over other options.

   • Set the connection string in code.

     Provide a connection string as part of the ApplicationInsightsServiceOptions argument to AddApplicationInsightsTelemetry in your program.cs class.

User secrets and other configuration providers

If you want to store the connection string in ASP.NET Core user secrets or retrieve it from another configuration provider, you can use the overload with a Microsoft.Extensions.Configuration.IConfiguration parameter. An example parameter is services.AddApplicationInsightsTelemetry(Configuration);.

In Microsoft.ApplicationInsights.AspNetCore version 2.15.0 and later, calling services.AddApplicationInsightsTelemetry() automatically reads the connection string from Microsoft.Extensions.Configuration.IConfiguration of the application. There's no need to explicitly provide IConfiguration.

If IConfiguration loaded configuration from multiple providers, then services.AddApplicationInsightsTelemetry prioritizes configuration from appsettings.json, irrespective of the order in which providers are added. Use the services.AddApplicationInsightsTelemetry(IConfiguration) method to read configuration from IConfiguration without this preferential treatment for appsettings.json.

To manually configure live metrics:

1. Install the NuGet package Microsoft.ApplicationInsights.PerfCounterCollector.

2. The following sample console app code shows setting up live metrics:

using Microsoft.ApplicationInsights;
using Microsoft.ApplicationInsights.Extensibility;
using Microsoft.ApplicationInsights.Extensibility.PerfCounterCollector.QuickPulse;
using System;
using System.Threading.Tasks;

namespace LiveMetricsDemo
{
    class Program
    {
        static void Main(string[] args)
        {
            // Create a TelemetryConfiguration instance.
            TelemetryConfiguration config = TelemetryConfiguration.CreateDefault();
            config.InstrumentationKey = "INSTRUMENTATION-KEY-HERE";
            QuickPulseTelemetryProcessor quickPulseProcessor = null;
            config.DefaultTelemetrySink.TelemetryProcessorChainBuilder
                .Use((next) =>
                {
                    quickPulseProcessor = new QuickPulseTelemetryProcessor(next);
                    return quickPulseProcessor;
                })
                .Build();

            var quickPulseModule = new QuickPulseTelemetryModule();

            // Secure the control channel.
            // This is optional, but recommended.
            quickPulseModule.AuthenticationApiKey = "YOUR-API-KEY-HERE";
            quickPulseModule.Initialize(config);
            quickPulseModule.RegisterTelemetryProcessor(quickPulseProcessor);

            // Create a TelemetryClient instance. It is important
            // to use the same TelemetryConfiguration here as the one
            // used to set up live metrics.
            TelemetryClient client = new TelemetryClient(config);

            // This sample runs indefinitely. Replace with actual application logic.
            while (true)
            {
                // Send dependency and request telemetry.
                // These will be shown in live metrics.
                // CPU/Memory Performance counter is also shown
                // automatically without any additional steps.
                client.TrackDependency("My dependency", "target", "http://sample",
                    DateTimeOffset.Now, TimeSpan.FromMilliseconds(300), true);
                client.TrackRequest("My Request", DateTimeOffset.Now,
                    TimeSpan.FromMilliseconds(230), "200", true);
                Task.Delay(1000).Wait();
            }
        }
    }
}

To manually configure live metrics:

1. Install the NuGet package Microsoft.ApplicationInsights.PerfCounterCollector.

2. The following sample console app code shows setting up live metrics:

using Microsoft.ApplicationInsights;
using Microsoft.ApplicationInsights.Extensibility;
using Microsoft.ApplicationInsights.Extensibility.PerfCounterCollector.QuickPulse;

// Create a TelemetryConfiguration instance.
TelemetryConfiguration config = TelemetryConfiguration.CreateDefault();
config.ConnectionString = "InstrumentationKey=00000000-0000-0000-0000-000000000000";
QuickPulseTelemetryProcessor quickPulseProcessor = null;
config.DefaultTelemetrySink.TelemetryProcessorChainBuilder
    .Use((next) =>
    {
        quickPulseProcessor = new QuickPulseTelemetryProcessor(next);
        return quickPulseProcessor;
    })
    .Build();

var quickPulseModule = new QuickPulseTelemetryModule();

// Secure the control channel.
// This is optional, but recommended.
quickPulseModule.AuthenticationApiKey = "YOUR-API-KEY-HERE";
quickPulseModule.Initialize(config);
quickPulseModule.RegisterTelemetryProcessor(quickPulseProcessor);

// Create a TelemetryClient instance. It is important
// to use the same TelemetryConfiguration here as the one
// used to set up live metrics.
TelemetryClient client = new TelemetryClient(config);

// This sample runs indefinitely. Replace with actual application logic.
while (true)
{
    // Send dependency and request telemetry.
    // These will be shown in live metrics.
    // CPU/Memory Performance counter is also shown
    // automatically without any additional steps.
    client.TrackDependency("My dependency", "target", "http://sample",
        DateTimeOffset.Now, TimeSpan.FromMilliseconds(300), true);
    client.TrackRequest("My Request", DateTimeOffset.Now,
        TimeSpan.FromMilliseconds(230), "200", true);
    Task.Delay(1000).Wait();
}

The preceding sample is for a console app, but the same code can be used in any .NET applications.

ILogger guidance doesn’t apply to ASP.NET. To send trace logs from classic ASP.NET apps to Application Insights, use supported adapters such as:

• System.Diagnostics.Trace with Application Insights TraceListener
• log4net or NLog with official Application Insights targets

For detailed steps and configuration examples, see Send trace logs to Application Insights.

The Application Insights SDK for ASP.NET Core already collects ILogger logs by default. If you use the SDK, you typically don’t need to also call builder.Logging.AddApplicationInsights() and can disregard the following ILogger installation instructions.

If you only need log forwarding and not the full telemetry stack, you can use the Microsoft.Extensions.Logging.ApplicationInsights provider package to capture logs.

Add ApplicationInsightsLoggerProvider

1. Install the Microsoft.Extensions.Logging.ApplicationInsights.

2. Add ApplicationInsightsLoggerProvider:

using Microsoft.Extensions.Logging.ApplicationInsights;

var builder = WebApplication.CreateBuilder(args);

// Add services to the container.

builder.Services.AddControllers();
// Learn more about configuring Swagger/OpenAPI at https://aka.ms/aspnetcore/swashbuckle
builder.Services.AddEndpointsApiExplorer();
builder.Services.AddSwaggerGen();

builder.Logging.AddApplicationInsights(
        configureTelemetryConfiguration: (config) => 
            config.ConnectionString = builder.Configuration.GetConnectionString("APPLICATIONINSIGHTS_CONNECTION_STRING"),
            configureApplicationInsightsLoggerOptions: (options) => { }
    );

builder.Logging.AddFilter<ApplicationInsightsLoggerProvider>("your-category", LogLevel.Trace);

var app = builder.Build();

// Configure the HTTP request pipeline.
if (app.Environment.IsDevelopment())
{
    app.UseSwagger();
    app.UseSwaggerUI();
}

app.UseHttpsRedirection();

app.UseAuthorization();

app.MapControllers();

app.Run();

With the NuGet package installed and the provider being registered with dependency injection, the app is ready to log. With constructor injection, either ILogger or the generic-type alternative ILogger<TCategoryName> is required. When these implementations are resolved, ApplicationInsightsLoggerProvider provides them. Logged messages or exceptions are sent to Application Insights.

Consider the following example controller:

public class ValuesController : ControllerBase
{
    private readonly ILogger _logger;

    public ValuesController(ILogger<ValuesController> logger)
    {
        _logger = logger;
    }

    [HttpGet]
    public ActionResult<IEnumerable<string>> Get()
    {
        _logger.LogWarning("An example of a Warning trace..");
        _logger.LogError("An example of an Error level message");

        return new string[] { "value1", "value2" };
    }
}

For more information, see Logging in ASP.NET Core and What Application Insights telemetry type is produced from ILogger logs? Where can I see ILogger logs in Application Insights?.

To automatically track dependencies from .NET console apps, install the NuGet package Microsoft.ApplicationInsights.DependencyCollector and initialize DependencyTrackingTelemetryModule:

    DependencyTrackingTelemetryModule depModule = new DependencyTrackingTelemetryModule();
    depModule.Initialize(TelemetryConfiguration.Active);

For .NET Core console apps, TelemetryConfiguration.Active is obsolete. See the guidance in the Worker service documentation and the ASP.NET Core tabs in this article.

For ASP.NET applications, the full SQL query text is collected with the help of byte code instrumentation, which requires using the instrumentation engine or by using the Microsoft.Data.SqlClient NuGet package instead of the System.Data.SqlClient library. Platform-specific steps to enable full SQL Query collection are described in the following table.

In addition to the preceding platform-specific steps, you must also explicitly opt in to enable SQL command collection by modifying the applicationInsights.config file with the following code:

<TelemetryModules>
  <Add Type="Microsoft.ApplicationInsights.DependencyCollector.DependencyTrackingTelemetryModule, Microsoft.AI.DependencyCollector">
    <EnableSqlCommandTextInstrumentation>true</EnableSqlCommandTextInstrumentation>
  </Add>

For ASP.NET Core applications, It's required to opt in to SQL Text collection by using:

services.ConfigureTelemetryModule<DependencyTrackingTelemetryModule>((module, o) => { module. EnableSqlCommandTextInstrumentation = true; });

To have exceptions reported from your server-side application, consider the following scenarios:

• Add the Application Insights Extension for Azure web apps.
• Add the Application Monitoring Extension for Azure Virtual Machines and Azure Virtual Machine Scale Sets IIS-hosted apps.
• Add the Application Insights SDK to your app code, run Application Insights Agent for IIS web servers, or enable the Java agent for Java web apps.

The JavaScript SDK provides the ability for client-side reporting of exceptions that occur in web browsers. To set up exception reporting on the client, see Application Insights for webpages.

With some application frameworks, more configuration is required. Consider the following technologies:

• Web forms
• MVC
• Web API 1.*
• Web API 2.*
• WCF

Application Insights comes with a curated Application Performance Management experience to help you diagnose failures in your monitored applications.

For detailed instructions, see Investigate failures, performance, and transactions with Application Insights.

1. Open the app solution in Visual Studio. Run the app, either on your server or on your development machine by using F5. Re-create the exception.

2. Open the Application Insights Search telemetry window in Visual Studio. While debugging, select the Application Insights dropdown box.

3. Select an exception report to show its stack trace. To open the relevant code file, select a line reference in the stack trace.

   If CodeLens is enabled, you see data about the exceptions:

   

var telemetry = new TelemetryClient();

try
{
    // ...
}
catch (Exception ex)
{
    var properties = new Dictionary<string, string>
    {
        ["Game"] = currentGame.Name
    };

    var measurements = new Dictionary<string, double>
    {
        ["Users"] = currentGame.Users.Count
    };

    // Send the exception telemetry:
    telemetry.TrackException(ex, properties, measurements);
}

try
{
    // ...
}
catch (ex)
{
    appInsights.trackException(ex, "handler loc",
    {
        Game: currentGame.Name,
        State: currentGame.State.ToString()
    });
}

Default counters for ASP.NET web applications:

• % Process\Processor Time
• % Process\Processor Time Normalized
• Memory\Available Bytes
• ASP.NET Requests/Sec
• .NET Common Language Runtime (CLR) Exceptions Thrown / sec
• ASP.NET ApplicationsRequest Execution Time
• Process\Private Bytes
• Process\IO Data Bytes/sec
• ASP.NET Applications\Requests In Application Queue
• Processor(_Total)\% Processor Time

Default counters for ASP.NET Core web applications:

• % Process\Processor Time
• % Process\Processor Time Normalized
• Memory\Available Bytes
• Process\Private Bytes
• Process\IO Data Bytes/sec
• Processor(_Total)\% Processor Time

Option 1: Configuration in ApplicationInsights.config

1. Find out what counters are available in your server by using this PowerShell command on the local server:

   Get-Counter -ListSet *
   

   For more information, see Get-Counter.

2. Open ApplicationInsights.config.

   If you added Application Insights to your app during development:

   1. Edit ApplicationInsights.config in your project.
   2. Redeploy it to your servers.

3. Edit the performance collector directive:

   
       <Add Type="Microsoft.ApplicationInsights.Extensibility.PerfCounterCollector.PerformanceCollectorModule, Microsoft.AI.PerfCounterCollector">
         <Counters>
           <Add PerformanceCounter="\Objects\Processes"/>
           <Add PerformanceCounter="\Sales(photo)\# Items Sold" ReportAs="Photo sales"/>
         </Counters>
       </Add>
   

You capture both standard counters and counters you implement yourself. \Objects\Processes is an example of a standard counter that's available on all Windows systems. \Sales(photo)\# Items Sold is an example of a custom counter that might be implemented in a web service.

The format is \Category(instance)\Counter, or for categories that don't have instances, just \Category\Counter.

The ReportAs parameter is required for counter names that don't match [a-zA-Z()/-_ \.]+.

If you specify an instance, it becomes a dimension CounterInstanceName of the reported metric.

Option 2: Configuration in code

See the following section.

Configure PerformanceCollectorModule after the WebApplication.CreateBuilder() method in Program.cs:

using Microsoft.ApplicationInsights.Extensibility.PerfCounterCollector;

var builder = WebApplication.CreateBuilder(args);

builder.Services.AddApplicationInsightsTelemetry();

// The following configures PerformanceCollectorModule.

builder.Services.ConfigureTelemetryModule<PerformanceCollectorModule>((module, o) =>
    {
        // The application process name could be "dotnet" for ASP.NET Core self-hosted applications.
        module.Counters.Add(new PerformanceCounterCollectionRequest(@"\Process([replace-with-application-process-name])\Page Faults/sec", "DotnetPageFaultsPerfSec"));
    });

var app = builder.Build();

The Application Insights .NET SDK consists of many NuGet packages. The core package provides the API for sending telemetry to the Application Insights. More packages provide telemetry modules and initializers for automatically tracking telemetry from your application and its context. By adjusting the configuration file, you can enable or disable telemetry modules and initializers. You can also set parameters for some of them.

The configuration file is named ApplicationInsights.config or ApplicationInsights.xml. The name depends on the type of your application. It's automatically added to your project when you install most versions of the SDK.

By default, when you use the automated experience from the Visual Studio template projects that support Add > Application Insights Telemetry, the ApplicationInsights.config file is created in the project root folder. After compiling, it gets copied to the bin folder. It's also added to a web app by Application Insights Agent on an IIS server.

There isn't an equivalent file to control the SDK in a webpage.

In ASP.NET Core applications, all configuration changes are made in the ConfigureServices() method of your Startup.cs class, unless otherwise directed.

Option 1: Configuration in code

The following code sets up a ServerTelemetryChannel instance with StorageFolder set to a custom location. Add this code at the beginning of the application, typically in the Application_Start() method in Global.aspx.cs.

using Microsoft.ApplicationInsights.Extensibility;
using Microsoft.ApplicationInsights.WindowsServer.TelemetryChannel;
protected void Application_Start()
{
    var serverTelemetryChannel = new ServerTelemetryChannel();
serverTelemetryChannel.StorageFolder = @"d:\temp\applicationinsights";
    serverTelemetryChannel.Initialize(TelemetryConfiguration.Active);
    TelemetryConfiguration.Active.TelemetryChannel = serverTelemetryChannel;
}

Option 2: Configuration in ApplicationInsights.config

The following section from ApplicationInsights.config shows the ServerTelemetryChannel channel configured with StorageFolder set to a custom location:

    <TelemetrySinks>
        <Add Name="default">
            <TelemetryProcessors>
                <!-- Telemetry processors omitted for brevity  -->
            </TelemetryProcessors>
            <TelemetryChannel Type="Microsoft.ApplicationInsights.WindowsServer.TelemetryChannel.ServerTelemetryChannel, Microsoft.AI.ServerTelemetryChannel">
                <StorageFolder>d:\temp\applicationinsights</StorageFolder>
            </TelemetryChannel>
        </Add>
    </TelemetrySinks>

Modify the ConfigureServices method of the Startup.cs class as shown here:

using Microsoft.ApplicationInsights.Channel;
using Microsoft.ApplicationInsights.WindowsServer.TelemetryChannel;

public void ConfigureServices(IServiceCollection services)
{
    // This sets up ServerTelemetryChannel with StorageFolder set to a custom location.
    services.AddSingleton(typeof(ITelemetryChannel), new ServerTelemetryChannel() {StorageFolder = @"d:\temp\applicationinsights" });

    services.AddApplicationInsightsTelemetry();
}

Overriding ServerTelemetryChannel

The default telemetry channel is ServerTelemetryChannel. The following example shows how to override it.

using Microsoft.ApplicationInsights.Channel;

var builder = WebApplication.CreateBuilder(args);

// Use the following to replace the default channel with InMemoryChannel.
// This can also be applied to ServerTelemetryChannel.
builder.Services.AddSingleton(typeof(ITelemetryChannel), new InMemoryChannel() {MaxTelemetryBufferCapacity = 19898 });

builder.Services.AddApplicationInsightsTelemetry();

var app = builder.Build();

Each telemetry module collects a specific type of data and uses the core API to send the data. The modules are installed by different NuGet packages, which also add the required lines to the .config file.

Use the TelemetryModules section in ApplicationInsights.config to configure, add, or remove modules. The following examples:

• Configure DependencyTrackingTelemetryModule (enable W3C header injection).
• Configure EventCounterCollectionModule (clear defaults and add a single counter).
• Disable perf‑counter collection by removing PerformanceCollectorModule.

<ApplicationInsights>
  <TelemetryModules>

    <!-- Dependency tracking -->
    <Add Type="Microsoft.ApplicationInsights.DependencyCollector.DependencyTrackingTelemetryModule, Microsoft.AI.DependencyCollector">
      <!-- Match Core example: enable W3C header injection -->
      <EnableW3CHeadersInjection>true</EnableW3CHeadersInjection>
    </Add>

    <!-- EventCounterCollectionModule: add a single counter (if you use event counters) -->
    <Add Type="Microsoft.ApplicationInsights.Extensibility.PerfCounterCollector.EventCounterCollectionModule, Microsoft.AI.PerfCounterCollector">
      <Counters>
        <!-- Mirrors Core example: only collect 'gen-0-size' from System.Runtime -->
        <Add ProviderName="System.Runtime" CounterName="gen-0-size" />
      </Counters>
    </Add>

    <!-- PerformanceCollectorModule (classic Windows performance counters).
         To DISABLE perf-counter collection, do NOT include this module.
         If it already exists in your file, remove or comment it out.
         Example of the line you would remove:
    <Add Type="Microsoft.ApplicationInsights.Extensibility.PerfCounterCollector.PerformanceCollectorModule, Microsoft.AI.PerfCounterCollector" />
    -->

  </TelemetryModules>
</ApplicationInsights>

Option 1: Configure telemetry modules using ConfigureTelemetryModule

To configure any default TelemetryModule, use the extension method ConfigureTelemetryModule<T> on IServiceCollection, as shown in the following example:

using Microsoft.ApplicationInsights.DependencyCollector;
using Microsoft.ApplicationInsights.Extensibility.PerfCounterCollector;

var builder = WebApplication.CreateBuilder(args);

builder.Services.AddApplicationInsightsTelemetry();

// The following configures DependencyTrackingTelemetryModule.
// Similarly, any other default modules can be configured.
builder.Services.ConfigureTelemetryModule<DependencyTrackingTelemetryModule>((module, o) =>
        {
            module.EnableW3CHeadersInjection = true;
        });

// The following removes all default counters from EventCounterCollectionModule, and adds a single one.
builder.Services.ConfigureTelemetryModule<EventCounterCollectionModule>((module, o) =>
        {
            module.Counters.Add(new EventCounterCollectionRequest("System.Runtime", "gen-0-size"));
        });

// The following removes PerformanceCollectorModule to disable perf-counter collection.
// Similarly, any other default modules can be removed.
var performanceCounterService = builder.Services.FirstOrDefault<ServiceDescriptor>(t => t.ImplementationType == typeof(PerformanceCollectorModule));
if (performanceCounterService != null)
{
    builder.Services.Remove(performanceCounterService);
}

var app = builder.Build();

Option 2: Configure telemetry modules using ApplicationInsightsServiceOptions

In SDK versions 2.12.2 and later, you can modify a few common settings by passing ApplicationInsightsServiceOptions to AddApplicationInsightsTelemetry, as in this example:

var builder = WebApplication.CreateBuilder(args);

var aiOptions = new Microsoft.ApplicationInsights.AspNetCore.Extensions.ApplicationInsightsServiceOptions();

// Disables adaptive sampling.
aiOptions.EnableAdaptiveSampling = false;

// Disables live metrics (also known as QuickPulse).
aiOptions.EnableQuickPulseMetricStream = false;

builder.Services.AddApplicationInsightsTelemetry(aiOptions);
var app = builder.Build();

This table has the full list of ApplicationInsightsServiceOptions settings:

For the most current list, see the configurable settings in ApplicationInsightsServiceOptions.

Configuration recommendation for Microsoft.ApplicationInsights.AspNetCore SDK 2.15.0 and later

In Microsoft.ApplicationInsights.AspNetCore SDK version 2.15.0 and later, configure every setting available in ApplicationInsightsServiceOptions, including ConnectionString. Use the application's IConfiguration instance. The settings must be under the section ApplicationInsights, as shown in the following example. The following section from appsettings.json configures the connection string and disables adaptive sampling and performance counter collection.

{
    "ApplicationInsights": {
    "ConnectionString": "InstrumentationKey=00000000-0000-0000-0000-000000000000",
    "EnableAdaptiveSampling": false,
    "EnablePerformanceCounterCollectionModule": false
    }
}

If builder.Services.AddApplicationInsightsTelemetry(aiOptions) for ASP.NET Core 6.0 or services.AddApplicationInsightsTelemetry(aiOptions) for ASP.NET Core 3.1 and earlier is used, it overrides the settings from Microsoft.Extensions.Configuration.IConfiguration.

There's a node in the configuration file for each module. To disable a module, delete the node or comment it out.

If you want to disable telemetry conditionally and dynamically, you can resolve the TelemetryConfiguration instance with an ASP.NET Core dependency injection container anywhere in your code and set the DisableTelemetry flag on it.

var builder = WebApplication.CreateBuilder(args);

builder.Services.AddApplicationInsightsTelemetry();

// any custom configuration can be done here:
builder.Services.Configure<TelemetryConfiguration>(x => x.DisableTelemetry = true);

var app = builder.Build();

The preceding code sample prevents the sending of telemetry to Application Insights. It doesn't prevent any automatic collection modules from collecting telemetry. If you want to remove a particular autocollection module, see telemetry modules.

Telemetry initializers set context properties that are sent along with every item of telemetry.

You can write your own initializers to set context properties.

The standard initializers are all set either by the web or WindowsServer NuGet packages:

To learn how to use telemetry initializers with ASP.NET applications, see Filter and preprocess telemetry in the Application Insights SDK.

Add any new TelemetryInitializer to the DependencyInjection container as shown in the following code. The SDK automatically picks up any TelemetryInitializer that's added to the DependencyInjection container.

var builder = WebApplication.CreateBuilder(args);

builder.Services.AddSingleton<ITelemetryInitializer, MyCustomTelemetryInitializer>();

var app = builder.Build();

Remove telemetry initializers

By default, telemetry initializers are present. To remove all or specific telemetry initializers, use the following sample code after calling AddApplicationInsightsTelemetry().

var builder = WebApplication.CreateBuilder(args);

builder.Services.AddApplicationInsightsTelemetry();

// Remove a specific built-in telemetry initializer
var tiToRemove = builder.Services.FirstOrDefault<ServiceDescriptor>
                    (t => t.ImplementationType == typeof(AspNetCoreEnvironmentTelemetryInitializer));
if (tiToRemove != null)
{
    builder.Services.Remove(tiToRemove);
}

// Remove all initializers
// This requires importing namespace by using Microsoft.Extensions.DependencyInjection.Extensions;
builder.Services.RemoveAll(typeof(ITelemetryInitializer));

var app = builder.Build();

Telemetry processors can filter and modify each telemetry item before it's sent from the SDK to the portal.

To learn how to use telemetry processors with ASP.NET applications, see Filter and preprocess telemetry in the Application Insights SDK.

You can write your own telemetry processors.

Adaptive sampling telemetry processor (from 2.0.0-beta3)

This functionality is enabled by default. If your app sends considerable telemetry, this processor removes some of it.

    <TelemetryProcessors>
      <Add Type="Microsoft.ApplicationInsights.WindowsServer.TelemetryChannel.AdaptiveSamplingTelemetryProcessor, Microsoft.AI.ServerTelemetryChannel">
        <MaxTelemetryItemsPerSecond>5</MaxTelemetryItemsPerSecond>
      </Add>
    </TelemetryProcessors>

The parameter provides the target that the algorithm tries to achieve. Each instance of the SDK works independently. So, if your server is a cluster of several machines, the actual volume of telemetry is multiplied accordingly.

Learn more about sampling.

Fixed-rate sampling telemetry processor (from 2.0.0-beta1)

There's also a standard sampling telemetry processor (from 2.0.1):

    <TelemetryProcessors>
     <Add Type="Microsoft.ApplicationInsights.WindowsServer.TelemetryChannel.SamplingTelemetryProcessor, Microsoft.AI.ServerTelemetryChannel">

     <!-- Set a percentage close to 100/N where N is an integer. -->
     <!-- E.g. 50 (=100/2), 33.33 (=100/3), 25 (=100/4), 20, 1 (=100/100), 0.1 (=100/1000) -->
     <SamplingPercentage>10</SamplingPercentage>
     </Add>
   </TelemetryProcessors>

You can add custom telemetry processors to TelemetryConfiguration by using the extension method AddApplicationInsightsTelemetryProcessor on IServiceCollection. You use telemetry processors in advanced filtering scenarios. Use the following example:

var builder = WebApplication.CreateBuilder(args);

// ...
builder.Services.AddApplicationInsightsTelemetry();
builder.Services.AddApplicationInsightsTelemetryProcessor<MyFirstCustomTelemetryProcessor>();

// If you have more processors:
builder.Services.AddApplicationInsightsTelemetryProcessor<MySecondCustomTelemetryProcessor>();

var app = builder.Build();

To set the connection string for all instances of TelemetryClient, including standard telemetry modules, do this step in an initialization method, such as global.aspx.cs in an ASP.NET service:

using Microsoft.ApplicationInsights.Extensibility;
using Microsoft.ApplicationInsights;

    protected void Application_Start()
    {
        TelemetryConfiguration configuration = TelemetryConfiguration.CreateDefault();
        configuration.ConnectionString = "InstrumentationKey=00000000-0000-0000-0000-000000000000";
        var telemetryClient = new TelemetryClient(configuration);

If you want to send a specific set of events to a different resource, you can set the key for a specific telemetry client:

    var tc = new TelemetryClient();
    tc.Context.ConnectionString = "InstrumentationKey=00000000-0000-0000-0000-000000000000";
    tc.TrackEvent("myEvent");
    // ...

To get a new connection string, create a new resource in the Application Insights portal.

In ASP.NET Core, configure the connection string in Program.cs during application startup using the TelemetryConfiguration from the dependency injection (DI) container:

using Microsoft.ApplicationInsights.Extensibility;
using Microsoft.ApplicationInsights;

var builder = WebApplication.CreateBuilder(args);

// Add Application Insights
builder.Services.AddApplicationInsightsTelemetry();

var app = builder.Build();

// Resolve TelemetryConfiguration from DI and set the connection string
var config = app.Services.GetRequiredService<TelemetryConfiguration>();
config.ConnectionString = "InstrumentationKey=00000000-0000-0000-0000-000000000000";

app.Run();

If you want to send a specific set of events to a different resource, you can create a new TelemetryClient instance and set its connection string explicitly:

using Microsoft.ApplicationInsights;

var tc = new TelemetryClient();
tc.Context.ConnectionString = "InstrumentationKey=00000000-0000-0000-0000-000000000000";
tc.TrackEvent("myEvent");
// ...

Example configuration via ApplicationInsights.config

<ApplicationInsights>
    ...
    <ApplicationIdProvider Type="Microsoft.ApplicationInsights.Extensibility.Implementation.ApplicationId.ApplicationInsightsApplicationIdProvider, Microsoft.ApplicationInsights">
        <ProfileQueryEndpoint>https://dc.services.visualstudio.com/api/profiles/{0}/appId</ProfileQueryEndpoint>
    </ApplicationIdProvider>
    ...
</ApplicationInsights>

Example configuration via code

TelemetryConfiguration.Active.ApplicationIdProvider = new ApplicationInsightsApplicationIdProvider();

[NOTE] In ASP.NET Core, there is no ApplicationInsights.config file. Configuration is done through dependency injection (DI) in Program.cs or Startup.cs.

You can override the default provider or customize its ProfileQueryEndpoint.

using Microsoft.ApplicationInsights.Extensibility.Implementation.ApplicationId;

var builder = WebApplication.CreateBuilder(args);

// Add Application Insights
builder.Services.AddApplicationInsightsTelemetry();

// Replace default provider with custom configuration
builder.Services.AddSingleton<IApplicationIdProvider>(sp =>
    new ApplicationInsightsApplicationIdProvider
    {
        ProfileQueryEndpoint = "https://custom-proxy/api/profiles/{0}/appId"
    });

var app = builder.Build();
app.Run();

Example configuration via ApplicationInsights.config

<ApplicationInsights>
    ...
    <ApplicationIdProvider Type="Microsoft.ApplicationInsights.Extensibility.Implementation.ApplicationId.DictionaryApplicationIdProvider, Microsoft.ApplicationInsights">
        <Defined>
            <Type key="InstrumentationKey_1" value="ApplicationId_1"/>
            <Type key="InstrumentationKey_2" value="ApplicationId_2"/>
        </Defined>
        <Next Type="Microsoft.ApplicationInsights.Extensibility.Implementation.ApplicationId.ApplicationInsightsApplicationIdProvider, Microsoft.ApplicationInsights" />
    </ApplicationIdProvider>
    ...
</ApplicationInsights>

Example configuration via code

TelemetryConfiguration.Active.ApplicationIdProvider = new DictionaryApplicationIdProvider{
 Defined = new Dictionary<string, string>
    {
        {"InstrumentationKey_1", "ApplicationId_1"},
        {"InstrumentationKey_2", "ApplicationId_2"}
    }
};

using Microsoft.ApplicationInsights.Extensibility.Implementation.ApplicationId;

var builder = WebApplication.CreateBuilder(args);

builder.Services.AddApplicationInsightsTelemetry();

// Register DictionaryApplicationIdProvider
builder.Services.AddSingleton<IApplicationIdProvider>(sp =>
    new DictionaryApplicationIdProvider
    {
        Defined = new Dictionary<string, string>
        {
            { "InstrumentationKey_1", "ApplicationId_1" },
            { "InstrumentationKey_2", "ApplicationId_2" }
        },
        Next = new ApplicationInsightsApplicationIdProvider() // optional fallback
    });

var app = builder.Build();
app.Run();

var requestTelemetry = HttpContext.Current?.Items["Microsoft.ApplicationInsights.RequestTelemetry"] as RequestTelemetry;

if (requestTelemetry != null)
{
    requestTelemetry.Properties["myProp"] = "someData";
}

HttpContext.Features.Get<RequestTelemetry>().Properties["myProp"] = someData

For the template-based ASP.NET MVC app from this article, the file that you need to edit is _Layout.cshtml. You can find it under Views > Shared. To add client-side monitoring, open _Layout.cshtml and follow the JavaScript (Web) SDK Loader Script-based setup instructions from the article about client-side JavaScript SDK configuration.

If your application has client-side components, follow the next steps to start collecting usage telemetry using JavaScript (Web) SDK Loader Script injection by configuration.

1. In _ViewImports.cshtml, add injection:

   @inject Microsoft.ApplicationInsights.AspNetCore.JavaScriptSnippet JavaScriptSnippet
   

2. In _Layout.cshtml, insert HtmlHelper at the end of the <head> section but before any other script. If you want to report any custom JavaScript telemetry from the page, inject it after this snippet:

       @Html.Raw(JavaScriptSnippet.FullScript)
   </head>
   

As an alternative to using FullScript, ScriptBody is available starting in Application Insights SDK for ASP.NET Core version 2.14. Use ScriptBody if you need to control the <script> tag to set a Content Security Policy:

<script> // apply custom changes to this script tag.
    @Html.Raw(JavaScriptSnippet.ScriptBody)
</script>

The .cshtml file names referenced earlier are from a default MVC application template. Ultimately, if you want to properly enable client-side monitoring for your application, the JavaScript (Web) SDK Loader Script must appear in the <head> section of each page of your application that you want to monitor. Add the JavaScript (Web) SDK Loader Script to _Layout.cshtml in an application template to enable client-side monitoring.

If your project doesn't include _Layout.cshtml, you can still add client-side monitoring by adding the JavaScript (Web) SDK Loader Script to an equivalent file that controls the <head> of all pages within your app. Alternatively, you can add the JavaScript (Web) SDK Loader Script to multiple pages, but we don't recommend it.