---

name: applicationinsights-web-ts description: Instrument browser/web apps with the Application Insights JavaScript SDK (@microsoft/applicationinsights-web). Use for Real User Monitoring (RUM) — page views, clicks, AJAX/fetch dependencies, exceptions, custom events, and browser-side GenAI agent traces correlated to backend OpenTelemetry traces. Covers SDK Loader Script and npm setup, framework extensions (React, React Native, Angular), Click Analytics, telemetry initializers, and OTel GenAI semantic conventions for agent/tool/model spans emitted from the browser. license: MIT metadata: author: Microsoft version: "1.0.0" package: "@microsoft/applicationinsights-web"

Application Insights JavaScript SDK (Web) for TypeScript

Real User Monitoring (RUM) for browser apps with @microsoft/applicationinsights-web. Auto-collects page views, AJAX/fetch dependencies, unhandled exceptions, and (with the Click Analytics plugin) clicks. Supports custom events, metrics, and GenAI agent traces that follow OpenTelemetry GenAI semantic conventions and correlate to backend spans via W3C Trace Context.

Distinct from azure-monitor-opentelemetry-ts, which is for Node.js server apps. This skill is for browser/web code (and React Native).

Before Implementation

Search microsoft-docs MCP for current API patterns:

• Query: "Application Insights JavaScript SDK setup"
• Query: "Application Insights JavaScript SDK configuration"
• Query: "Application Insights JavaScript framework extensions React Angular"
• Verify package version: npm view @microsoft/applicationinsights-web version

Packages

| Package | Purpose | | --- | --- | | @microsoft/applicationinsights-web | Core RUM SDK (page views, AJAX, exceptions). | | @microsoft/applicationinsights-clickanalytics-js | Auto-collect click telemetry. | | @microsoft/applicationinsights-react-js | React plugin (router instrumentation, hooks, HOC, ErrorBoundary). | | @microsoft/applicationinsights-react-native | React Native plugin (native crashes, sessions). | | @microsoft/applicationinsights-angularplugin-js | Angular plugin (router events, ErrorHandler). | | @microsoft/applicationinsights-debugplugin-js | Dev-only telemetry inspector. | | @microsoft/applicationinsights-perfmarkmeasure-js | User Timing (performance.mark/measure) integration. |

Installation

npm i --save @microsoft/applicationinsights-web
# Optional plugins (install only what you use):
npm i --save @microsoft/applicationinsights-clickanalytics-js
npm i --save @microsoft/applicationinsights-react-js @microsoft/applicationinsights-react-native @microsoft/applicationinsights-angularplugin-js

Typings ship with the package — no separate @types/... install needed.

Connection String

The browser SDK requires a connection string at init time. It ships in plaintext to clients — Microsoft Entra ID auth is not supported for browser telemetry. Use a separate App Insights resource with local auth enabled for browser RUM if you need to isolate it from backend telemetry.

# Vite / CRA / Next.js — expose to client via the public env prefix
VITE_APPINSIGHTS_CONNECTION_STRING="InstrumentationKey=...;IngestionEndpoint=https://...;LiveEndpoint=https://..."
NEXT_PUBLIC_APPINSIGHTS_CONNECTION_STRING="InstrumentationKey=..."

Quick Start (npm)

import { ApplicationInsights } from "@microsoft/applicationinsights-web";

export const appInsights = new ApplicationInsights({
  config: {
    connectionString: import.meta.env.VITE_APPINSIGHTS_CONNECTION_STRING,
    enableAutoRouteTracking: true,        // SPA route changes -> page views
    enableCorsCorrelation: true,          // propagate Request-Id / traceparent to cross-origin AJAX
    enableRequestHeaderTracking: true,
    enableResponseHeaderTracking: true,
    distributedTracingMode: 2,            // DistributedTracingModes.AI_AND_W3C — emit traceparent for backend correlation
    autoTrackPageVisitTime: true,
    disableFetchTracking: false,          // fetch() is auto-instrumented by default
    excludeRequestFromAutoTrackingPatterns: [/livemetrics\.azure\.com/i]
  }
});

appInsights.loadAppInsights();
appInsights.trackPageView();

Call loadAppInsights() exactly once, as early as possible (before user interactions you want tracked). Then trackPageView() for the initial load — when enableAutoRouteTracking is on, subsequent route changes are automatic.

Quick Start (SDK Loader Script)

Recommended when you want auto-updating SDK and zero build pipeline. Paste this as the first <script> in <head>:

<script type="text/javascript" src="https://js.monitor.azure.com/scripts/b/ai.3.gbl.min.js" crossorigin="anonymous"></script>
<script type="text/javascript">
  var appInsights = window.appInsights || function (cfg) {
    /* See: https://learn.microsoft.com/azure/azure-monitor/app/javascript-sdk
       Use the latest snippet from the Microsoft Learn page above — it includes
       backup-CDN failover (cr), SDK-load-failure reporting, and the queue shim
       so calls before SDK ready are not lost. */
  }({ src: "https://js.monitor.azure.com/scripts/b/ai.3.gbl.min.js",
      crossOrigin: "anonymous",
      cfg: { connectionString: "YOUR_CONNECTION_STRING" } });
</script>

Loader-only API (queued until SDK loads): trackEvent, trackPageView, trackException, trackTrace, trackDependencyData, trackMetric, trackPageViewPerformance, startTrackPage, stopTrackPage, startTrackEvent, stopTrackEvent, addTelemetryInitializer, setAuthenticatedUserContext, clearAuthenticatedUserContext, flush.

Core Tracking APIs

// Page views (SPAs that disable enableAutoRouteTracking)
appInsights.trackPageView({ name: "Checkout", uri: "/checkout", properties: { cartSize: 3 } });

// Custom events (user actions, business events)
appInsights.trackEvent({ name: "PurchaseCompleted" }, { orderId: "ord_123", amountUsd: 49.95 });

// Exceptions (caught errors)
try {
  await pay(order);
} catch (err) {
  appInsights.trackException({ exception: err as Error, severityLevel: 3, properties: { orderId: order.id } });
}

// Traces (logs, severity 0=Verbose, 1=Info, 2=Warning, 3=Error, 4=Critical)
appInsights.trackTrace({ message: "Cart hydrated from local storage", severityLevel: 1 });

// Custom metrics (numeric)
appInsights.trackMetric({ name: "checkout.duration_ms", average: 1234 });

// Dependencies (manually-tracked outbound calls — fetch/XHR are auto-tracked)
appInsights.trackDependencyData({
  id: crypto.randomUUID(),
  name: "GET /api/orders",
  duration: 87, success: true, responseCode: 200,
  data: "https://api.example.com/api/orders", target: "api.example.com", type: "Fetch"
});

// User identity (set ONCE per authenticated session — values are PII; do not pass emails)
appInsights.setAuthenticatedUserContext("user-id-123", "tenant-456", /*storeInCookie*/ true);
appInsights.clearAuthenticatedUserContext(); // on logout

// Force send before unload
appInsights.flush();

Telemetry Initializers (enrichment & filtering)

Run for every envelope before send. Return false to drop.

import type { ITelemetryItem } from "@microsoft/applicationinsights-web";

appInsights.addTelemetryInitializer((item: ITelemetryItem) => {
  item.tags ??= {};
  item.tags["ai.cloud.role"] = "web-shop";
  item.tags["ai.cloud.roleInstance"] = window.location.hostname;
  item.data ??= {};
  item.data["app.version"] = import.meta.env.VITE_APP_VERSION;
  item.data["app.build"] = import.meta.env.VITE_BUILD_SHA;

  // Drop noisy health-check page views
  if (item.baseType === "PageviewData" && item.baseData?.uri?.endsWith("/healthz")) return false;

  // Scrub query-string secrets
  if (item.baseData?.uri) {
    item.baseData.uri = item.baseData.uri.replace(/([?&](token|sig|key)=)[^&]+/gi, "$1REDACTED");
  }
});

Click Analytics

import { ClickAnalyticsPlugin } from "@microsoft/applicationinsights-clickanalytics-js";

const clickPlugin = new ClickAnalyticsPlugin();
const appInsights = new ApplicationInsights({
  config: {
    connectionString: import.meta.env.VITE_APPINSIGHTS_CONNECTION_STRING,
    extensions: [clickPlugin],
    extensionConfig: {
      [clickPlugin.identifier]: {
        autoCapture: true,
        dataTags: { useDefaultContentNameOrId: true, customDataPrefix: "data-ai-" },
        urlCollectHash: false,
        behaviorValidator: (b: string) => /^[a-z0-9_]+$/.test(b) ? b : ""
      }
    }
  }
});
appInsights.loadAppInsights();

Mark elements with data-ai-* attributes; clicks are emitted as Custom Events with parent-content metadata.

SPA Route Tracking

• Built-in: set enableAutoRouteTracking: true. Hooks history.pushState/replaceState and popstate.
• React Router: use @microsoft/applicationinsights-react-js withAITracking HOC (see references/framework-extensions.md).
• Manual: call appInsights.trackPageView({ name, uri }) in your router's useEffect on route change. Disable enableAutoRouteTracking to avoid double counting.

Distributed Tracing (correlate to backend)

Set distributedTracingMode: 2 (DistributedTracingModes.AI_AND_W3C). The SDK adds traceparent (and legacy Request-Id) to outbound fetch/XHR. Backends instrumented with OpenTelemetry (e.g. @azure/monitor-opentelemetry) auto-link to the browser's operation_Id.

For cross-origin calls, also set enableCorsCorrelation: true and add the calling origin to the CORS exposed headers on the API.

GenAI Agent Traces (OTel semantic conventions)

When the browser invokes an AI agent (function-calling, tool-use, model calls direct from the client), emit App Insights Dependency telemetry whose attributes follow the OpenTelemetry GenAI semantic conventions so they are queryable alongside backend agent spans in App Insights / Log Analytics.

Set the opt-in env first so backend instrumentations agree on the same schema version:

OTEL_SEMCONV_STABILITY_OPT_IN=gen_ai_latest_experimental

Required attribute keys (use the OTel names verbatim)

| Span / op | Required attributes | | --- | --- | | invoke_agent {agent.name} | gen_ai.operation.name=invoke_agent, gen_ai.provider.name, gen_ai.agent.name, gen_ai.agent.id (when known) | | create_agent {agent.name} | gen_ai.operation.name=create_agent, gen_ai.provider.name, gen_ai.agent.name, gen_ai.request.model | | chat {model} | gen_ai.operation.name=chat, gen_ai.provider.name, gen_ai.request.model, gen_ai.response.model, gen_ai.usage.input_tokens, gen_ai.usage.output_tokens | | execute_tool {tool.name} | gen_ai.operation.name=execute_tool, gen_ai.tool.name, gen_ai.tool.type (function | extension | datastore), gen_ai.tool.call.id |

gen_ai.provider.name well-known values: openai, azure.ai.openai, azure.ai.inference, anthropic, aws.bedrock, gcp.gemini, gcp.vertex_ai, cohere, mistral_ai, groq, deepseek, perplexity, x_ai, ibm.watsonx.ai.

Sensitive content opt-in. gen_ai.system_instructions, gen_ai.input.messages, gen_ai.output.messages, gen_ai.tool.call.arguments, gen_ai.tool.call.result are Opt-In by default. Gate them behind a runtime flag and avoid them in production unless you have approved data handling.

Pattern: invoke_agent + nested tool/model spans

import { ApplicationInsights, SeverityLevel } from "@microsoft/applicationinsights-web";

type GenAiAttrs = Record<string, string | number | boolean | undefined>;

function startGenAiSpan(name: string, attrs: GenAiAttrs) {
  const id = crypto.randomUUID();
  const start = performance.now();
  const baseProps: GenAiAttrs = { "gen_ai.span.id": id, ...attrs };
  return {
    end(success: boolean, extra: GenAiAttrs = {}, error?: Error) {
      const duration = Math.round(performance.now() - start);