Application Insights for Node.js

Application Insights SDK monitors your backend services and components after you deploy them to help you discover and rapidly diagnose performance and other issues. Add this SDK to your Node.js services to include deep info about Node.js processes and their external dependencies such as database and cache services. You can use this SDK for your Node.js services hosted anywhere: your datacenter, Azure VMs and Web Apps, and even other public clouds. This solution is based on OpenTelemetry, to learn more about OpenTelemetry concepts, see the OpenTelemetry overview or OpenTelemetry FAQ.

Supported Node.js versions

Important: The Azure Monitor OpenTelemetry-based Offerings for Node.js applications do not support older versions of Node that were supported by Application Insights 2.X SDK. If you rely on this support, please continue to use version 2.X.

We support the versions of Node.js that are supported by OpenTelemetry.

Limitations of Application Insights 3.X SDK

In order to support importing version 3.X SDK as an ESM module, please follow the OpenTelemetry project's documentation on using the instrumentation hook.

Consider whether this version is right for you. It enables distributed tracing, metrics, logs and excludes:

• Autopopulation of Cloud Role Name and Cloud Role Instance in Azure environments
• Autopopulation of User ID and Authenticated User ID when you use the Application Insights JavaScript SDK
• Autopopulation of User IP (to determine location attributes)
• Ability to override Operation Name
• Ability to manually set User ID or Authenticated User ID
• Propagating Operation Name to Dependency Telemetry

Warning: This SDK only works for Node.js environments. Use the Application Insights JavaScript SDK for web and browser scenarios.

To determine if this version of Application Insights is right for you, review the Application Insights 2.X SDK migration guide.

Prerequisites

• Azure subscription: Create an Azure subscription for free

• Application Insights resource: Create an Application Insights resource

• Application using an officially supported version of Node.js runtime:

  • OpenTelemetry supported runtimes
  • Azure Monitor OpenTelemetry Exporter supported runtimes

Get started

Important: On March 31st, 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.

1. Create an Application Insights resource in Azure by following these instructions.
2. Grab the Connection String from the resource you created in step 1. Later, you'll either add it to your app's environment variables or use it directly in your scripts.
3. Add the Application Insights Node.js SDK to your app's dependencies and package.json:

    npm install --save applicationinsights

   Note: If you're using TypeScript, please install @types/node package to prevent build issues, this npm package contains built-in typings.

4. As early as possible in your app's code, load the Application Insights package:

    let appInsights = require('applicationinsights');

5. Configure the local SDK by calling appInsights.setup('YOUR_CONNECTION_STRING');, using the connection string you grabbed in step 2. Or put it in the APPLICATIONINSIGHTS_CONNECTION_STRING environment variable and call appInsights.setup() without parameters.

   For more configuration options see below.

6. Finally, start automatically collecting and sending data by calling appInsights.start();.

• If the connection string is set in the environment variable APPLICATIONINSIGHTS_CONNECTION_STRING, .setup() can be called with no arguments. This makes it easy to use different connection strings for different environments.

Load the Application Insights library (i.e. require("applicationinsights")) as early as possible in your scripts, before loading other packages. This is needed so that the Application Insights library can prepare later packages for tracking. If you encounter conflicts with other libraries doing similar preparation, try loading the Application Insights library after those.

Configuration

The appInsights object provides a number of methods to setup SDK behavior. They are listed in the following snippet with their default values.

let appInsights = require("applicationinsights");
appInsights.setup("<YOUR_CONNECTION_STRING>")
    .setAutoCollectRequests(true)
    .setAutoCollectPerformance(true, true)
    .setAutoCollectExceptions(true)
    .setAutoCollectDependencies(true)
    .setAutoCollectConsole(true, false)
    .setAutoCollectPreAggregatedMetrics(true)
    .setSendLiveMetrics(false)
    .setInternalLogging(false, true)
    .enableWebInstrumentation(false)
    .start();

Please review their descriptions in your IDE's built-in type hinting, or applicationinsights.ts for detailed information on what these control, and optional secondary arguments.

Note that by default setAutoCollectConsole is configured to exclude calls to console.log (and other console methods). By default, only calls to supported third-party loggers (e.g. winston, bunyan) will be collected. You can change this behavior to include calls to console methods by using setAutoCollectConsole(true, true).

Note that by default enableWebInstrumentation will use the connection string for SDK initialization. If you want to use a different one, you can set it as enableWebInstrumentation(true, "your-connection-string").

The TelemetryClient object contains a config property with many optional settings. These can be set as follows:

client.config.PROPERTYNAME = VALUE;

These properties are client specific, so you can configure appInsights.defaultClient separately from clients created with new appInsights.TelemetryClient().

All these properties except aadTokenCredential could be configured using configuration file applicationinsights.json located under root folder of applicationinsights package installation folder, Ex: node_modules/applicationinsights. These configuration values will be applied to all TelemetryClients created in the SDK.

{
    "samplingPercentage": 80,
    "enableAutoCollectExternalLoggers": true,
    "enableAutoCollectExceptions": true,
    "enableSendLiveMetrics": true,
    ...
}

Custom JSON file could be provided using APPLICATIONINSIGHTS_CONFIGURATION_FILE environment variable.

process.env.APPLICATIONINSIGHTS_CONFIGURATION_FILE = "C:/applicationinsights/config/customConfig.json"

// Application Insights SDK setup....

Alternatively, instead of using a configuration file, you can specify the entire content of the JSON configuration via the environment variable APPLICATIONINSIGHTS_CONFIGURATION_CONTENT.

Sampling

By default, the SDK will send all collected data to the Application Insights service. If you collect a lot of data, you might want to enable sampling to reduce the amount of data sent. Set the samplingPercentage field on the Config object of a Client to accomplish this. Setting samplingPercentage to 100 (the default) means all data will be sent, and 0 means nothing will be sent.

If you are using automatic correlation, all data associated with a single request will be included or excluded as a unit.

Add code such as the following to enable sampling:

const appInsights = require("applicationinsights");
appInsights.setup("<YOUR_CONNECTION_STRING>");
appInsights.defaultClient.config.samplingPercentage = 33; // 33% of all telemetry will be sent to Application Insights
appInsights.start();

Automatic web Instrumentation

For node server with configuration enableWebInstrumentation set to true or environment variable APPLICATIONINSIGHTS_WEB_INSTRUMENTATION_ENABLED = true, web Instrumentation will be enabled on node server response when all of the following requirements are met:

• Response has status code 200.
• Response method is GET.
• Sever response has Content-Type html.
• Server response must have both <head> and </head> Tags.
• If response is compressed, it must have only one Content-Encoding type, and encoding type must be one of gzip, br or deflate.
• Response does not contain current /backup web Instrumentation CDN endpoints. (current and backup Web Instrumentation CDN endpoints here)

web Instrumentation CDN endpoint can be changed by setting environment variable APPLICATIONINSIGHTS_WEB_INSTRUMENTATION_SOURCE = "web Instrumentation CDN endpoints". web Instrumentation connection string can be changed by setting environment variable APPLICATIONINSIGHTS_WEB_INSTRUMENTATION_CONNECTION_STRING = "web Instrumentation connection string"

Note: web Instrumentation may slow down server response time, especially when response size is large or response is compressed. For the case in which some middle layers are applied, it may result in web Instrumentation not working and original response will be returned.

Automatic third-party instrumentation

If you require further third-party instrumenatations please use the Azure Monitor OpenTelemetry Distro to take advantage of OpenTelemetry. If you are an Application Insights 2.X SDK user, a migration guide is available.

In order to track context across asynchronous calls, some changes are required in third party libraries such as mongodb and redis. By default ApplicationInsights will use the appropriate OpenTelemetry instrumentation for each library. This can be disabled by setting the APPLICATION_INSIGHTS_NO_DIAGNOSTIC_CHANNEL environment variable. Note that by setting that environment variable, events may no longer be correctly associated with the right operation. Individual instrumentations can be disabled by setting the APPLICATION_INSIGHTS_NO_PATCH_MODULES environment variable to a comma separated list of packages to disable, e.g. APPLICATION_INSIGHTS_NO_PATCH_MODULES=console,redis to avoid patching the console and redis packages.

The following modules are available: azuresdk, bunyan, console, mongodb, mongodb-core, mysql, redis, winston, pg, and pg-pool.

Automatic instrumentation for several Azure SDKs is also enabled. Javascript Azure SDKs

The bunyan, winston, and console patches will generate Application Insights Trace events based on whether setAutoCollectConsole is enabled. The rest will generate Application Insights Dependency events based on whether setAutoCollectDependencies is enabled. Make sure that applicationinsights is imported before any 3rd-party packages for them to be instrumented successfully.

Live Metrics

To enable sending live metrics of your app to Azure, use setSendLiveMetrics(true). Filtering of live metrics in the Portal is currently not supported.

Track custom telemetry

You can track any request, event, metric or exception using the Application Insights client. Examples follow:

let appInsights = require("applicationinsights");
appInsights.setup().start(); // assuming connection string is in environment variables. start() can be omitted to disable any non-custom data
let client = appInsights.defaultClient;
client.trackEvent({name: "my custom event", properties: {customProperty: "custom property value"}});
client.trackException({exception: new Error("handled exceptions can be logged with this method")});
client.trackMetric({name: "custom metric", value: 3});
client.trackTrace({message: "trace message"});
client.trackDependency({target:"http://dbname", name:"select customers proc", data:"SELECT * FROM Customers", duration:231, resultCode:0, success: true, dependencyTypeName: "ZSQL"});
client.trackRequest({name:"GET /customers", url:"http://myserver/customers", duration:309, resultCode:200, success:true});
client.trackAvailability({id: "123456789abcdefghijklmnopqrstuvw", name: "availalaibility-test-name", duration: 1000, success: true, runLocation: "Japan East", message: "Passed"})

let http = require("http");
http.createServer( (req, res) => {
  client.trackNodeHttpRequest({request: req, response: res}); // Place at the beginning of your request handler
});

Note that custom properties are converted to their string representation before being sent, see Using properties for more information.

An example utility using trackMetric to measure how long event loop scheduling takes:

function startMeasuringEventLoop() {
  var startTime = process.hrtime();
  var sampleSum = 0;
  var sampleCount = 0;

  // Measure event loop scheduling delay
  setInterval(() => {
    var elapsed = process.hrtime(startTime);
    startTime = process.hrtime();
    sampleSum += elapsed[0] * 1e9 + elapsed[1];
    sampleCount++;
  }, 0);

  // Report custom metric every second
  setInterval(() => {
    var samples = sampleSum;
    var count = sampleCount;
    sampleSum = 0;
    sampleCount = 0;

    if (count > 0) {
      var avgNs = samples / count;
      var avgMs = Math.round(avgNs / 1e6);
      client.trackMetric({name: "Event Loop Delay", value: avgMs});
    }
  }, 1000);
}

Self-diagnostics

"Self-diagnostics" refers to internal logging from Application Insights Node.js SDK.

This functionality can be helpful for spotting and diagnosing issues with Application Insights itself.

By default, Application Insights Node.js SDK logs at warning level to console, following code demonstrate how to enable debug logging as well and generate telemetry for internal logs:

let appInsights = require("applicationinsights");
appInsights.setup("<YOUR_CONNECTION_STRING>")
    .setInternalLogging(true, true) // Enable both debug and warning logging
    .setAutoCollectConsole(true, true) // Generate Trace telemetry for winston/bunyan and console logs
    .start();

Debug Logs could be enabled as well using APPLICATION_INSIGHTS_ENABLE_DEBUG_LOGS environment variable, and APPLICATION_INSIGHTS_DISABLE_WARNING_LOGS environment variable to disable warnings. Logs could be put into local file using APPLICATIONINSIGHTS_LOG_DESTINATION environment variable, supported values are file and file+console, a file named applicationinsights.log will be generated on tmp folder by default, including all logs, /tmp for *nix and USERDIR/AppData/Local/Temp for Windows. Log directory could be configured using APPLICATIONINSIGHTS_LOGDIR environment variable.

process.env.APPLICATIONINSIGHTS_LOG_DESTINATION = "file";
process.env.APPLICATIONINSIGHTS_LOGDIR = "C:/applicationinsights/logs"

// Application Insights SDK setup....

ApplicationInsights 3.X SDK Unsupported Properties

Application Insights 3.X SDK will provide support path for customers who only require basic instrumentation as opposed to migrating to Azure Monitor OpenTelemetry. If unsupported methods are called, they are not breaking and your application will still run. Calling these unsupported methods will throw a warning that the method is not supported.

The following methods are called after using the below method.

let applicationinsights = require("applicationinsights");
appinsights.setup("<YOUR_CONNECTION_STRING>").start();

The following configurations are set using either environment variables, setting them in the applicationinsights.json file or by calling appInsights.defaultClient.config.<CONFIG_SETTING_VALUE>;.

The following methods are part of the TelemetryClient class. They can be called using applicationinsights.defaultClient.<METHOD_NAME>().

APPLICATIONINSIGHTS_INSTRUMENTATION_LOGGING_LEVEL environment varialbe could be used to set desired log level, supporting the following values: NONE, ERROR, WARN, INFO, DEBUG, VERBOSE and ALL.

Logs could be put into local file using APPLICATIONINSIGHTS_LOG_DESTINATION environment variable, supported values are file and file+console, a file named applicationinsights.log will be generated on tmp folder by default, including all logs, /tmp for *nix and USERDIR/AppData/Local/Temp for Windows. Log directory could be configured using APPLICATIONINSIGHTS_LOGDIR environment variable.

process.env.APPLICATIONINSIGHTS_INSTRUMENTATION_LOGGING_LEVEL = "VERBOSE";
process.env.APPLICATIONINSIGHTS_LOG_DESTINATION = "file";
process.env.APPLICATIONINSIGHTS_LOGDIR = "C:/applicationinsights/logs";

// Application Insights SDK setup....

Support

For help and questions about using this project, please create a Support request issue on https://github.com/microsoft/ApplicationInsights-node.js/issues.

For OpenTelemetry issues, contact the OpenTelemetry JavaScript community directly. Support Policy

Contributing

This project welcomes contributions and suggestions. Most contributions require you to agree to a Contributor License Agreement (CLA) declaring that you have the right to, and actually do, grant us the rights to use your contribution. For details, visit https://cla.microsoft.com.

When you submit a pull request, a CLA-bot will automatically determine whether you need to provide a CLA and decorate the PR appropriately (e.g., label, comment). Simply follow the instructions provided by the bot. You will only need to do this once across all repositories using our CLA.

This project has adopted the Microsoft Open Source Code of Conduct. For more information see the Code of Conduct FAQ or contact opencode@microsoft.com with any additional questions or comments.

Data Collection

As this SDK is designed to enable applications to perform data collection which is sent to the Microsoft collection endpoints the following is required to identify our privacy statement.

The software may collect information about you and your use of the software and send it to Microsoft. Microsoft may use this information to provide services and improve our products and services. You may turn off the telemetry as described in the repository. There are also some features in the software that may enable you and Microsoft to collect data from users of your applications. If you use these features, you must comply with applicable law, including providing appropriate notices to users of your applications together with a copy of Microsoft’s privacy statement. Our privacy statement is located at https://go.microsoft.com/fwlink/?LinkID=824704. You can learn more about data collection and use in the help documentation and our privacy statement. Your use of the software operates as your consent to these practices.

Trademarks

This project may contain trademarks or logos for projects, products, or services. Authorized use of Microsoft trademarks or logos is subject to and must follow Microsoft’s Trademark & Brand Guidelines. Use of Microsoft trademarks or logos in modified versions of this project must not cause confusion or imply Microsoft sponsorship. Any use of third-party trademarks or logos are subject to those third-party’s policies.

License

MIT