Application Insights for web pages


We continue to assess the viability of OpenTelemetry for browser scenarios. The Application Insights JavaScript SDK is recommended for the forseeable future, which is fully compatible with OpenTelemetry distributed tracing.

Find out about the performance and usage of your web page or app. If you add Application Insights to your page script, you get timings of page loads and AJAX calls, counts, and details of browser exceptions and AJAX failures, as well as users and session counts. All of this telemetry can be segmented by page, client OS and browser version, geo location, and other dimensions. You can set alerts on failure counts or slow page loading. And by inserting trace calls in your JavaScript code, you can track how the different features of your web page application are used.

Application Insights can be used with any web pages - you just add a short piece of JavaScript, Node.js has a standalone SDK. If your web service is Java or ASP.NET, you can use the server-side SDKs with the client-side JavaScript SDK to get an end-to-end understanding of your app's performance.

Adding the JavaScript SDK

  1. First you need an Application Insights resource. If you don't already have a resource and connection string, follow the create a new resource instructions.
  2. Copy the connection string for the resource where you want your JavaScript telemetry to be sent (from step 1.) You'll add it to the connectionString setting of the Application Insights JavaScript SDK.
  3. Add the Application Insights JavaScript SDK to your web page or app via one of the following two options:


@microsoft/applicationinsights-web-basic - AISKULight does not support the use of connection strings.


Only use one method to add the JavaScript SDK to your application. If you use the NPM Setup, don't use the Snippet and vice versa.


NPM Setup installs the JavaScript SDK as a dependency to your project, enabling IntelliSense, whereas the Snippet fetches the SDK at runtime. Both support the same features. However, developers who desire more custom events and configuration generally opt for NPM Setup whereas users looking for quick enablement of out-of-the-box web analytics opt for the Snippet.

npm based setup

Install via Node Package Manager (npm).

npm i --save @microsoft/applicationinsights-web


Typings are included with this package, so you do not need to install a separate typings package.

import { ApplicationInsights } from '@microsoft/applicationinsights-web'

const appInsights = new ApplicationInsights({ config: {
  connectionString: 'Copy connection string from Application Insights Resource Overview'
  /* ...Other Configuration Options... */
} });
appInsights.trackPageView(); // Manually call trackPageView to establish the current user/session/pageview

Snippet based setup

If your app doesn't use npm, you can directly instrument your webpages with Application Insights by pasting this snippet at the top of each your pages. Preferably, it should be the first script in your <head> section so that it can monitor any potential issues with all of your dependencies and optionally any JavaScript errors. If you're using Blazor Server App, add the snippet at the top of the file _Host.cshtml in the <head> section.

Starting from version 2.5.5, the page view event will include a new tag "ai.internal.snippet" that contains the identified snippet version. This feature assists with tracking which version of the snippet your application is using.

The current Snippet (listed below) is version "5", the version is encoded in the snippet as sv:"#" and the current version is also available on GitHub.

<script type="text/javascript">
!function(T,l,y){var S=T.location,k="script",D="connectionString",C="ingestionendpoint",I="disableExceptionTracking",E="ai.device.",b="toLowerCase",w="crossOrigin",N="POST",e="appInsightsSDK",||"appInsights";(||T[e])&&(T[e]=t);var n=T[t]||function(d){var g=!1,f=!1,m={initialize:!0,queue:[],sv:"5",version:2,config:d};function v(e,t){var n={},a="Browser";return n[E+"id"]=a[b](),n[E+"type"]=a,n[""]=S&&S.pathname||"_unknown_",n["ai.internal.sdkVersion"]="javascript:snippet_"+(||m.version),{time:function(){var e=new Date;function t(e){var t=""+e;return 1===t.length&&(t="0"+t),t}return e.getUTCFullYear()+"-"+t(1+e.getUTCMonth())+"-"+t(e.getUTCDate())+"T"+t(e.getUTCHours())+":"+t(e.getUTCMinutes())+":"+t(e.getUTCSeconds())+"."+((e.getUTCMilliseconds()/1e3).toFixed(3)+"").slice(2,5)+"Z"}(),name:"Microsoft.ApplicationInsights."+e.replace(/-/g,"")+"."+t,sampleRate:100,tags:n,data:{baseData:{ver:2}}}}var h=d.url||y.src;if(h){function a(e){var t,n,a,i,r,o,s,c,u,p,l;g=!0,m.queue=[],f||(f=!0,t=h,s=function(){var e={},t=d.connectionString;if(t)for(var n=t.split(";"),a=0;a<n.length;a++){var i=n[a].split("=");2===i.length&&(e[i[0][b]()]=i[1])}if(!e[C]){var r=e.endpointsuffix,o=r?e.location:null;e[C]="https://"+(o?o+".":"")+"dc."+(r||"")}return e}(),c=s[D]||d[D]||"",u=s[C],p=u?u+"/v2/track":d.endpointUrl,(l=[]).push((n="SDK LOAD Failure: Failed to load Application Insights SDK script (See stack for details)",a=t,i=p,(o=(r=v(c,"Exception")).data).baseType="ExceptionData",o.baseData.exceptions=[{typeName:"SDKLoadFailed",message:n.replace(/\./g,"-"),hasFullStack:!1,stack:n+"\nSnippet failed to load ["+a+"] -- Telemetry is disabled\nHelp Link:\nHost: "+(S&&S.pathname||"_unknown_")+"\nEndpoint: "+i,parsedStack:[]}],r)),l.push(function(e,t,n,a){var i=v(c,"Message"),;r.baseType="MessageData";var o=r.baseData;return o.message='AI (Internal): 99 message:"'+("SDK LOAD Failure: Failed to load Application Insights SDK script (See stack for details) ("+n+")").replace(/\"/g,"")+'"',{endpoint:a},i}(0,0,t,p)),function(e,t){if(JSON){var n=T.fetch;if(n&&!y.useXhr)n(t,{method:N,body:JSON.stringify(e),mode:"cors"});else if(XMLHttpRequest){var a=new XMLHttpRequest;,t),a.setRequestHeader("Content-type","application/json"),a.send(JSON.stringify(e))}}}(l,p))}function i(e,t){f||setTimeout(function(){!t&&m.core||a()},500)}var e=function(){var n=l.createElement(k);n.src=h;var e=y[w];return!e&&""!==e||"undefined"==n[w]||(n[w]=e),n.onload=i,n.onerror=a,n.onreadystatechange=function(e,t){"loaded"!==n.readyState&&"complete"!==n.readyState||i(0,t)},n}();y.ld<0?l.getElementsByTagName("head")[0].appendChild(e):setTimeout(function(){l.getElementsByTagName(k)[0].parentNode.appendChild(e)},y.ld||0)}try{m.cookie=l.cookie}catch(p){}function t(e){for(;e.length;)!function(t){m[t]=function(){var e=arguments;g||m.queue.push(function(){m[t].apply(m,e)})}}(e.pop())}var n="track",r="TrackPage",o="TrackEvent";t([n+"Event",n+"PageView",n+"Exception",n+"Trace",n+"DependencyData",n+"Metric",n+"PageViewPerformance","start"+r,"stop"+r,"start"+o,"stop"+o,"addTelemetryInitializer","setAuthenticatedUserContext","clearAuthenticatedUserContext","flush"]),m.SeverityLevel={Verbose:0,Information:1,Warning:2,Error:3,Critical:4};var s=(d.extensionConfig||{}).ApplicationInsightsAnalytics||{};if(!0!==d[I]&&!0!==s[I]){var c="onerror";t(["_"+c]);var u=T[c];T[c]=function(e,t,n,a,i){var r=u&&u(e,t,n,a,i);return!0!==r&&m["_"+c]({message:e,url:t,lineNumber:n,columnNumber:a,error:i}),r},d.autoExceptionInstrumented=!0}return m}(y.cfg);function a(){y.onInit&&y.onInit(n)}(T[t]=n).queue&&0===n.queue.length?(n.queue.push(a),n.trackPageView({})):a()}(window,document,{
src: "", // The SDK URL Source
// name: "appInsights", // Global SDK Instance name defaults to "appInsights" when not supplied
// ld: 0, // Defines the load delay (in ms) before attempting to load the sdk. -1 = block page load and add to head. (default) = 0ms load after timeout,
// useXhr: 1, // Use XHR instead of fetch to report failures (if available),
crossOrigin: "anonymous", // When supplied this will add the provided value as the cross origin attribute on the script tag
// onInit: null, // Once the application insights instance has loaded and initialized this callback function will be called with 1 argument -- the sdk instance (DO NOT ADD anything to the sdk.queue -- As they won't get called)
cfg: { // Application Insights Configuration
    connectionString: "Copy connection string from Application Insights Resource Overview"
    /* ...Other Configuration Options... */


For readability and to reduce possible JavaScript errors, all of the possible configuration options are listed on a new line in snippet code above, if you don't want to change the value of a commented line it can be removed.

Reporting Script load failures

This version of the snippet detects and reports failures when loading the SDK from the CDN as an exception to the Azure Monitor portal (under the failures > exceptions > browser). The exception provides visibility into failures of this type so that you're aware your application isn't reporting telemetry (or other exceptions) as expected. This signal is an important measurement in understanding that you have lost telemetry because the SDK didn't load or initialize which can lead to:

  • Under-reporting of how users are using (or trying to use) your site;
  • Missing telemetry on how your end users are using your site;
  • Missing JavaScript errors that could potentially be blocking your end users from successfully using your site.

For details on this exception see the SDK load failure troubleshooting page.

Reporting of this failure as an exception to the portal doesn't use the configuration option disableExceptionTracking from the application insights configuration and therefore if this failure occurs it will always be reported by the snippet, even when the window.onerror support is disabled.

Reporting of SDK load failures isn't supported on Internet Explorer 8 or earlier. This behavior reduces the minified size of the snippet by assuming that most environments aren't exclusively IE 8 or less. If you have this requirement and you wish to receive these exceptions, you'll need to either include a fetch poly fill or create your own snippet version that uses XDomainRequest instead of XMLHttpRequest, it's recommended that you use the provided snippet source code as a starting point.


If you are using a previous version of the snippet, it is highly recommended that you update to the latest version so that you will receive these previously unreported issues.

Snippet configuration options

All configuration options have been moved towards the end of the script. This placement avoids accidentally introducing JavaScript errors that wouldn't just cause the SDK to fail to load, but also it would disable the reporting of the failure.

Each configuration option is shown above on a new line, if you don't wish to override the default value of an item listed as [optional] you can remove that line to minimize the resulting size of your returned page.

The available configuration options are

Name Type Description
src string [required] The full URL for where to load the SDK from. This value is used for the "src" attribute of a dynamically added <script /> tag. You can use the public CDN location or your own privately hosted one.
name string [optional] The global name for the initialized SDK, defaults to appInsights. So window.appInsights will be a reference to the initialized instance. Note: if you provide a name value or a previous instance appears to be assigned (via the global name appInsightsSDK) then this name value will also be defined in the global namespace as window.appInsightsSDK=<name value>. The SDK initialization code uses this reference to ensure it's initializing and updating the correct snippet skeleton and proxy methods.
ld number in ms [optional] Defines the load delay to wait before attempting to load the SDK. Default value is 0ms and any negative value will immediately add a script tag to the <head> region of the page, which will then block the page load event until to script is loaded (or fails).
useXhr boolean [optional] This setting is used only for reporting SDK load failures. Reporting will first attempt to use fetch() if available and then fallback to XHR, setting this value to true just bypasses the fetch check. Use of this value is only be required if your application is being used in an environment where fetch would fail to send the failure events.
crossOrigin string [optional] By including this setting, the script tag added to download the SDK will include the crossOrigin attribute with this string value. When not defined (the default) no crossOrigin attribute is added. Recommended values aren't defined (the default); ""; or "anonymous" (For all valid values see HTML attribute: crossorigin documentation)
cfg object [required] The configuration passed to the Application Insights SDK during initialization.

Connection String Setup


On March 31, 2025, support for instrumentation key ingestion will end. Instrumentation key ingestion will continue to work, but we'll no longer provide updates or support for the feature. Transition to connection strings to take advantage of new capabilities.

import { ApplicationInsights } from '@microsoft/applicationinsights-web'

const appInsights = new ApplicationInsights({ config: {
  /* ...Other Configuration Options... */
} });

Sending telemetry to the Azure portal

By default, the Application Insights JavaScript SDK auto-collects many telemetry items that are helpful in determining the health of your application and the underlying user experience.

This telemetry includes:

  • Uncaught exceptions in your app, including information on
    • Stack trace
    • Exception details and message accompanying the error
    • Line & column number of error
    • URL where error was raised
  • Network Dependency Requests made by your app XHR and Fetch (fetch collection is disabled by default) requests, include information on
    • Url of dependency source
    • Command & Method used to request the dependency
    • Duration of the request
    • Result code and success status of the request
    • ID (if any) of user making the request
    • Correlation context (if any) where request is made
  • User information (for example, Location, network, IP)
  • Device information (for example, Browser, OS, version, language, model)
  • Session information

Telemetry initializers

Telemetry initializers are used to modify the contents of collected telemetry before being sent from the user's browser. They can also be used to prevent certain telemetry from being sent, by returning false. Multiple telemetry initializers can be added to your Application Insights instance, and they're executed in order of adding them.

The input argument to addTelemetryInitializer is a callback that takes a ITelemetryItem as an argument and returns a boolean or void. If returning false, the telemetry item isn't sent, else it proceeds to the next telemetry initializer, if any, or is sent to the telemetry collection endpoint.

An example of using telemetry initializers:

var telemetryInitializer = (envelope) => { = 'This item passed through my telemetry initializer';
appInsights.trackTrace({message: 'This message will use a telemetry initializer'});

appInsights.addTelemetryInitializer(() => false); // Nothing is sent after this is executed
appInsights.trackTrace({message: 'this message will not be sent'}); // Not sent


Most configuration fields are named such that they can be defaulted to false. All fields are optional except for connectionString.

Name Description Default
connectionString Required
Connection string that you obtained from the Azure portal.
accountId An optional account ID, if your app groups users into accounts. No spaces, commas, semicolons, equals, or vertical bars string
sessionRenewalMs A session is logged if the user is inactive for this amount of time in milliseconds. numeric
(30 mins)
sessionExpirationMs A session is logged if it has continued for this amount of time in milliseconds. numeric
(24 hours)
maxBatchSizeInBytes Max size of telemetry batch. If a batch exceeds this limit, it's immediately sent and a new batch is started numeric
maxBatchInterval How long to batch telemetry for before sending (milliseconds) numeric
disable​ExceptionTracking If true, exceptions aren't autocollected. boolean
disableTelemetry If true, telemetry isn't collected or sent. boolean
enableDebug If true, internal debugging data is thrown as an exception instead of being logged, regardless of SDK logging settings. Default is false.
Note: Enabling this setting will result in dropped telemetry whenever an internal error occurs. This setting can be useful for quickly identifying issues with your configuration or usage of the SDK. If you don't want to lose telemetry while debugging, consider using loggingLevelConsole or loggingLevelTelemetry instead of enableDebug.
loggingLevelConsole Logs internal Application Insights errors to console.
0: off,
1: Critical errors only,
2: Everything (errors & warnings)
loggingLevelTelemetry Sends internal Application Insights errors as telemetry.
0: off,
1: Critical errors only,
2: Everything (errors & warnings)
diagnosticLogInterval (internal) Polling interval (in ms) for internal logging queue numeric
samplingPercentage Percentage of events that will be sent. Default is 100, meaning all events are sent. Set this option if you wish to preserve your data cap for large-scale applications. numeric
autoTrackPageVisitTime If true, on a pageview, the previous instrumented page's view time is tracked and sent as telemetry and a new timer is started for the current pageview. It's sent as a custom metric named PageVisitTime in milliseconds and is calculated via the Date now() function (if available) and falls back to (new Date()).getTime() if now() is unavailable (IE8 or less). Default is false. boolean
disableAjaxTracking If true, Ajax calls aren't autocollected. boolean
disableFetchTracking If true, Fetch requests aren't autocollected. boolean
overridePageViewDuration If true, default behavior of trackPageView is changed to record end of page view duration interval when trackPageView is called. If false and no custom duration is provided to trackPageView, the page view performance is calculated using the navigation timing API. boolean
maxAjaxCallsPerView Default 500 - controls how many Ajax calls will be monitored per page view. Set to -1 to monitor all (unlimited) Ajax calls on the page. numeric
disableDataLossAnalysis If false, internal telemetry sender buffers will be checked at startup for items not yet sent. boolean
disable​CorrelationHeaders If false, the SDK will add two headers ('Request-Id' and 'Request-Context') to all dependency requests to correlate them with corresponding requests on the server side. boolean
correlationHeader​ExcludedDomains Disable correlation headers for specific domains string[]
correlationHeader​ExcludePatterns Disable correlation headers using regular expressions regex[]
correlationHeader​Domains Enable correlation headers for specific domains string[]
disableFlush​OnBeforeUnload If true, flush method won't be called when onBeforeUnload event triggers boolean
enableSessionStorageBuffer If true, the buffer with all unsent telemetry is stored in session storage. The buffer is restored on page load boolean
cookieCfg Defaults to cookie usage enabled see ICookieCfgConfig settings for full defaults. ICookieCfgConfig
(Since 2.6.0)
If true, the SDK won't store or read any data from cookies. Disables the User and Session cookies and renders the usage blades and experiences useless. isCookieUseDisable is deprecated in favor of disableCookiesUsage, when both are provided disableCookiesUsage takes precedence.
(Since v2.6.0) And if cookieCfg.enabled is also defined it will take precedence over these values, Cookie usage can be re-enabled after initialization via the core.getCookieMgr().setEnabled(true).
alias for cookieCfg.enabled
cookieDomain Custom cookie domain. This option is helpful if you want to share Application Insights cookies across subdomains.
(Since v2.6.0) If cookieCfg.domain is defined it will take precedence over this value.
alias for cookieCfg.domain
cookiePath Custom cookie path. This option is helpful if you want to share Application Insights cookies behind an application gateway.
If cookieCfg.path is defined it will take precedence over this value.
alias for cookieCfg.path
(Since 2.6.0)
isRetryDisabled If false, retry on 206 (partial success), 408 (timeout), 429 (too many requests), 500 (internal server error), 503 (service unavailable), and 0 (offline, only if detected) boolean
isStorageUseDisabled If true, the SDK won't store or read any data from local and session storage. boolean
isBeaconApiDisabled If false, the SDK will send all telemetry using the Beacon API boolean
onunloadDisableBeacon When tab is closed, the SDK will send all remaining telemetry using the Beacon API boolean
sdkExtension Sets the sdk extension name. Only alphabetic characters are allowed. The extension name is added as a prefix to the 'ai.internal.sdkVersion' tag (for example, 'ext_javascript:2.0.0'). string
isBrowserLink​TrackingEnabled If true, the SDK will track all Browser Link requests. boolean
appId AppId is used for the correlation between AJAX dependencies happening on the client-side with the server-side requests. When Beacon API is enabled, it can’t be used automatically, but can be set manually in the configuration. string
enable​CorsCorrelation If true, the SDK will add two headers ('Request-Id' and 'Request-Context') to all CORS requests to correlate outgoing AJAX dependencies with corresponding requests on the server side. boolean
namePrefix An optional value that will be used as name postfix for localStorage and cookie name. string
enable​AutoRoute​Tracking Automatically track route changes in Single Page Applications (SPA). If true, each route change will send a new Pageview to Application Insights. Hash route changes ( are also recorded as new page views. boolean
enableRequest​HeaderTracking If true, AJAX & Fetch request headers is tracked. boolean
enableResponse​HeaderTracking If true, AJAX & Fetch request's response headers is tracked. boolean
distributedTracingMode Sets the distributed tracing mode. If AI_AND_W3C mode or W3C mode is set, W3C trace context headers (traceparent/tracestate) will be generated and included in all outgoing requests. AI_AND_W3C is provided for back-compatibility with any legacy Application Insights instrumented services. See example here. DistributedTracingModesor
(Since v2.6.0) DistributedTracingModes.AI_AND_W3C
(v2.5.11 or earlier) DistributedTracingModes.AI
enable​AjaxErrorStatusText If true, include response error data text in dependency event on failed AJAX requests. boolean
enable​AjaxPerfTracking Flag to enable looking up and including more browser window.performance timings in the reported ajax (XHR and fetch) reported metrics. boolean
maxAjaxPerf​LookupAttempts The maximum number of times to look for the window.performance timings (if available). This option is sometimes required as not all browsers populate the window.performance before reporting the end of the XHR request and for fetch requests this is added after its complete. numeric
ajaxPerfLookupDelay The amount of time to wait before reattempting to find the window.performance timings for an ajax request, time is in milliseconds and is passed directly to setTimeout(). numeric
25 ms
enableUnhandled​PromiseRejection​Tracking If true, unhandled promise rejections will be autocollected and reported as a JavaScript error. When disableExceptionTracking is true (don't track exceptions), the config value will be ignored and unhandled promise rejections won't be reported. boolean
enablePerfMgr When enabled (true) this will create local perfEvents for code that has been instrumented to emit perfEvents (via the doPerf() helper). This option can be used to identify performance issues within the SDK based on your usage or optionally within your own instrumented code. More details are available by the basic documentation. Since v2.5.7 boolean
perfEvtsSendAll When enablePerfMgr is enabled and the IPerfManager fires a INotificationManager.perfEvent() this flag determines whether an event is fired (and sent to all listeners) for all events (true) or only for 'parent' events (false <default>).
A parent IPerfEvent is an event where no other IPerfEvent is still running at the point of this event being created and its parent property isn't null or undefined. Since v2.5.7
idLength The default length used to generate new random session and user ID values. Defaults to 22, previous default value was 5 (v2.5.8 or less), if you need to keep the previous maximum length you should set this value to 5. numeric

From version 2.6.0, cookie management is now available directly from the instance and can be disabled and re-enabled after initialization.

If disabled during initialization via the disableCookiesUsage or cookieCfg.enabled configurations, you can now re-enable via the ICookieMgr setEnabled function.

The instance based cookie management also replaces the previous CoreUtils global functions of disableCookies(), setCookie(...), getCookie(...) and deleteCookie(...). And to benefit from the tree-shaking enhancements also introduced as part of version 2.6.0 you should no longer uses the global functions.


Cookie Configuration for instance-based cookie management added in version 2.6.0.

Name Description Type and Default
enabled A boolean that indicates whether the use of cookies by the SDK is enabled by the current instance. If false, the instance of the SDK initialized by this configuration won't store or read any data from cookies boolean
domain Custom cookie domain, which is helpful if you want to share Application Insights cookies across subdomains. If not provided uses the value from root cookieDomain value. string
path Specifies the path to use for the cookie, if not provided it will use any value from the root cookiePath value. string
getCookie Function to fetch the named cookie value, if not provided it will use the internal cookie parsing / caching. (name: string) => string
setCookie Function to set the named cookie with the specified value, only called when adding or updating a cookie. (name: string, value: string) => void
delCookie Function to delete the named cookie with the specified value, separated from setCookie to avoid the need to parse the value to determine whether the cookie is being added or removed. If not provided it will use the internal cookie parsing / caching. (name: string, value: string) => void

Enable time-on-page tracking

By setting autoTrackPageVisitTime: true, the time in milliseconds a user spends on each page is tracked. On each new PageView, the duration the user spent on the previous page is sent as a custom metric named PageVisitTime. This custom metric is viewable in the Metrics Explorer as a "log-based metric".

Enable Distributed Tracing

Correlation generates and sends data that enables distributed tracing and powers the application map, end-to-end transaction view, and other diagnostic tools.

In JavaScript correlation is turned off by default in order to minimize the telemetry we send by default. The following examples show standard configuration options for enabling correlation.

The following sample code shows the configurations required to enable correlation:

// excerpt of the config section of the JavaScript SDK snippet with correlation
// between client-side AJAX and server requests enabled.
cfg: { // Application Insights Configuration
    connectionString: "Copy connection string from Application Insights Resource Overview"
    enableCorsCorrelation: true,
    enableRequestHeaderTracking: true,
    enableResponseHeaderTracking: true,
    correlationHeaderExcludedDomains: ['*']
    /* ...Other Configuration Options... */


There are two distributed tracing modes/protocols - AI (Classic) and W3C TraceContext (New). In version 2.6.0 and later, they are both enabled by default. For older versions, users need to explicitly opt-in to WC3 mode.

Route tracking

By default, this SDK will not handle state-based route changing that occurs in single page applications. To enable automatic route change tracking for your single page application, you can add enableAutoRouteTracking: true to your setup configuration.

Single Page Applications

For Single Page Applications, reference plugin documentation for plugin specific guidance.

React Native
Click Analytics Auto-collection

Advanced Correlation

When a page is first loading and the SDK hasn't fully initialized, we're unable to generate the Operation ID for the first request. As a result, distributed tracing is incomplete until the SDK fully initializes. To remedy this problem, you can include dynamic JavaScript on the returned HTML page. The SDK will use a callback function during initialization to retroactively pull the Operation ID from the serverside and populate the clientside with it.

Here's a sample of how to create a dynamic JS using Razor:

!function(T,l,y){<removed snippet code>,{
    src: "", // The SDK URL Source
    onInit: function(appInsights) {
        var serverId = "@this.Context.GetRequestTelemetry().Context.Operation.Id";
        appInsights.context.telemetryTrace.parentID = serverId;
    cfg: { // Application Insights Configuration
        instrumentationKey: "YOUR_INSTRUMENTATION_KEY_GOES_HERE"


The application UX is not yet optimized to show these "first hop" advanced distributed tracing scenarios. However, the data will be available in the requests table for query and diagnostics.


React Native
Click Analytics Auto-collection

Explore browser/client-side data

Browser/client-side data can be viewed by going to Metrics and adding individual metrics you're interested in:

Screenshot of the Metrics page in Application Insights showing graphic displays of metrics data for a web application.

You can also view your data from the JavaScript SDK via the Browser experience in the portal.

Select Browser and then choose Failures or Performance.

Screenshot of the Browser page in Application Insights showing how to add Browser Failures or Browser Performance to the metrics that you can view for your web application.


Screenshot of the Performance page in Application Insights showing graphic displays of Operations metrics for a web application.


Screenshot of the Performance page in Application Insights showing graphic displays of Dependency metrics for a web application.


To query your telemetry collected by the JavaScript SDK, select the View in Logs (Analytics) button. By adding a where statement of client_Type == "Browser", you'll only see data from the JavaScript SDK and any server-side telemetry collected by other SDKs will be excluded.

// average pageView duration by name
let timeGrain=5m;
let dataset=pageViews
// additional filters can be applied here
| where timestamp > ago(1d)
| where client_Type == "Browser" ;
// calculate average pageView duration for all pageViews
| summarize avg(duration) by bin(timestamp, timeGrain)
| extend pageView='Overall'
// render result in a chart
| render timechart

Source Map Support

The minified callstack of your exception telemetry can be unminified in the Azure portal. All existing integrations on the Exception Details panel will work with the newly unminified callstack.

You can link your Application Insights resource to your own Azure Blob Storage container to automatically unminify call stacks. To get started, see automatic source map support.

Drag and drop

  1. Select an Exception Telemetry item in the Azure portal to view its "End-to-end transaction details"
  2. Identify which source maps correspond to this call stack. The source map must match a stack frame's source file, but suffixed with .map
  3. Drag and drop the source maps onto the call stack in the Azure portal An animated image showing how to drag and drop source map files from a build folder into the Call Stack window in the Azure portal.

Application Insights Web Basic

For a lightweight experience, you can instead install the basic version of Application Insights

npm i --save @microsoft/applicationinsights-web-basic

This version comes with the bare minimum number of features and functionalities and relies on you to build it up as you see fit. For example, it performs no autocollection (uncaught exceptions, AJAX, etc.). The APIs to send certain telemetry types, like trackTrace, trackException, etc., aren't included in this version, so you'll need to provide your own wrapper. The only API that is available is track. A sample is located here.


For runnable examples, see Application Insights JavaScript SDK Samples.

Upgrading from the old version of Application Insights

Breaking changes in the SDK V2 version:

  • To allow for better API signatures, some of the API calls, such as trackPageView and trackException, have been updated. Running in Internet Explorer 8 and earlier versions of the browser isn't supported.
  • The telemetry envelope has field name and structure changes due to data schema updates.
  • Moved context.operation to context.telemetryTrace. Some fields were also changed ( --> telemetryTrace.traceID).
    • To manually refresh the current pageview ID (for example, in SPA apps), use = Microsoft.ApplicationInsights.Telemetry.Util.generateW3CId().


      To keep the trace ID unique, where you previously used Util.newId(), now use Util.generateW3CId(). Both ultimately end up being the operation ID.

If you're using the current application insights PRODUCTION SDK (1.0.20) and want to see if the new SDK works in runtime, update the URL depending on your current SDK loading scenario.

  • Download via CDN scenario: Update the code snippet that you currently use to point to the following URL:

  • npm scenario: Call downloadAndSetup to download the full ApplicationInsights script from CDN and initialize it with a connection string:

       connectionString: "Copy connection string from Application Insights Resource Overview",
       url: ""

Test in internal environment to verify monitoring telemetry is working as expected. If all works, update your API signatures appropriately to SDK V2 version and deploy in your production environments.

SDK performance/overhead

At just 36 KB gzipped, and taking only ~15 ms to initialize, Application Insights adds a negligible amount of loadtime to your website. Minimal components of the library are quickly loaded when using this snippet. In the meantime, the full script is downloaded in the background.

While the script is downloading from the CDN, all tracking of your page is queued. Once the downloaded script finishes asynchronously initializing, all events that were queued are tracked. As a result, you won't lose any telemetry during the entire life cycle of your page. This setup process provides your page with a seamless analytics system, invisible to your users.


  • npm version
  • gzip compressed size
  • 15 ms overall initialization time
  • Zero tracking missed during life cycle of page

Browser support

Chrome Firefox IE Opera Safari
Chrome Latest ✔ Firefox Latest ✔ IE 9+ & Microsoft Edge ✔
IE 8- Compatible
Opera Latest ✔ Safari Latest ✔

ES3/IE8 Compatibility

As such we need to ensure that this SDK continues to "work" and doesn't break the JS execution when loaded by an older browser. It would be ideal to not support older browsers, but numerous large customers can’t control which browser their end users choose to use.

This statement does NOT mean that we'll only support the lowest common set of features. We need to maintain ES3 code compatibility and when adding new features, they'll need to be added in a manner that wouldn't break ES3 JavaScript parsing and added as an optional feature.

See GitHub for full details on IE8 support

Open-source SDK

The Application Insights JavaScript SDK is open-source to view the source code or to contribute to the project visit the official GitHub repository.

For the latest updates and bug fixes, consult the release notes.


I'm getting an error message of Failed to get Request-Context correlation header as it may be not included in the response or not accessible

The correlationHeaderExcludedDomains configuration property is an exclude list that disables correlation headers for specific domains. This option is useful when including those headers would cause the request to fail or not be sent due to third-party server configuration. This property supports wildcards. An example would be *, as seen in the code sample above. Adding the application domain to this property should be avoided as it stops the SDK from including the required distributed tracing Request-Id, Request-Context and traceparent headers as part of the request.

I'm not sure how to update my third-party server configuration

The server-side needs to be able to accept connections with those headers present. Depending on the Access-Control-Allow-Headers configuration on the server-side it's often necessary to extend the server-side list by manually adding Request-Id, Request-Context and traceparent (W3C distributed header).

Access-Control-Allow-Headers: Request-Id, traceparent, Request-Context, <your header>

I'm receiving duplicate telemetry data from the Application Insights JavaScript SDK

If the SDK reports correlation recursively, enable the configuration setting of excludeRequestFromAutoTrackingPatterns to exclude the duplicate data. This scenario can occur when using connection strings. The syntax for the configuration setting is excludeRequestFromAutoTrackingPatterns: [<endpointUrl>].

Next steps