ApplicationInsights-JS
Microsoft's Application Insights JavaScript SDK is a production-grade browser monitoring library that tracks page views, performance metrics, exceptions, and custom events in web applications. It integrates with Azure Application Insights for centralized observability and supports both NPM and snippet-based deployment.
Key facts
Objective fields from the source. Values we can't verify are shown as “Unknown” rather than guessed.
| Field | Value |
|---|---|
| Repository | microsoft/ApplicationInsights-JS |
| Owner | microsoft |
| Primary language | TypeScript |
| License | MIT — OSI-approved |
| Stars | 684 |
| Forks | 254 |
| Open issues | 88 |
| Latest release | v3.4.1 (2026-04-07) |
| Last updated | 2026-07-02 |
| Source | https://github.com/microsoft/ApplicationInsights-JS |
What ApplicationInsights-JS is
TypeScript-based SDK for client-side telemetry collection with support for OpenTelemetry tracing APIs, dynamic configuration, tree-shaking, and multiple deployment modes. V3.x (current) requires ES5+ (IE9+) and removes IE8 support; v2.x is feature-frozen and receives critical fixes only.
Get the ApplicationInsights-JS source
Clone the repository and explore it locally.
git clone https://github.com/microsoft/ApplicationInsights-JS.gitcd ApplicationInsights-JS# follow the project's README for install & configurationNeed it deployed, integrated, or customized instead? DEV.co ships production installs.
Best use cases
Implementation considerations
- Latest CDN endpoint must be used (js.monitor.azure.com, not deprecated az416426.vo.msecnd.net) to avoid outage.
- V3.x introduces breaking changes from v2.x; migration requires code review and testing.
- Multiple major versions active in same session can cause conflicts; consolidate SDK versions.
- Snippet-based deployment preferred for earliest error capture but requires manual placement in all pages.
- TypeScript typings included; no separate @types package needed.
When to avoid it — and what to weigh
- Node.js backend instrumentation needed — SDK is browser-only; Node.js apps require the separate ApplicationInsights-node.js repository.
- IE8 or ES3 support required — V3.x (current) requires ES5+; legacy v1.x or v2.x branches required for older browser support.
- Privacy-critical applications with strict data residency — Data flows to Azure endpoints; requires confirmation of acceptable data handling and regional compliance.
- Non-Azure observability platforms — SDK is tightly coupled to Application Insights backend; custom endpoint configuration possible but not the primary design pattern.
License & commercial use
MIT License. Permissive OSI-approved license allowing commercial use, modification, and distribution with no warranty.
MIT license permits commercial use without restrictions. No license fees. Ensure compliance with dependency licenses in the project. Data transmission to Azure services incurs Application Insights service costs (subject to Azure pricing).
DEV.co evaluation signals
Editorial assessment — not user reviews. Directional, with an explicit confidence level.
| Signal | Assessment |
|---|---|
| Maintenance | Active |
| Documentation | Adequate |
| License clarity | Clear |
| Deployment complexity | Low |
| DEV.co fit | Strong |
| Assessment confidence | High |
Data in transit to Azure; HTTPS used. No security audit details, vulnerability disclosure process, or known CVEs referenced in provided data. Assess Azure data handling policies and regional compliance requirements. SDK runs in browser context; no elevation of privilege or sandboxing provided. Update regularly to receive security patches.
Alternatives to consider
Datadog RUM
Vendor-agnostic SPA monitoring with real user monitoring, session replay, and error tracking; integrates with non-Azure backends.
New Relic Browser
Comprehensive browser observability with synthetic monitoring, custom instrumentation, and multi-cloud support.
Sentry
Error and performance monitoring focused on exception tracking and release health; lighter weight, no hard Azure dependency.
Build on ApplicationInsights-JS with DEV.co software developers
Use the Application Insights JavaScript SDK to track user behavior, performance metrics, and errors in production. Install via NPM or deploy as a snippet in minutes.
Talk to DEV.coRelated open-source tools
Surfaced by semantic similarity across the DEV.co open-source index.
Related on DEV.co
Explore the category and the services that help you build with it.
ApplicationInsights-JS FAQ
Can I use this in a Node.js application?
Do I need a separate typings package?
What is the CDN migration issue mentioned in the README?
Can I upgrade from v2.x to v3.x without code changes?
Custom software development services
Adopting ApplicationInsights-JS is usually one piece of a larger software development effort. As a software development agency, DEV.co provides software development services and web development expertise — pairing senior software developers and web developers with your team to design, build, and operate open-source observability software in production.
Integrate Browser Monitoring into Your Web Application
Use the Application Insights JavaScript SDK to track user behavior, performance metrics, and errors in production. Install via NPM or deploy as a snippet in minutes.