Bugsnag notifier for node.js scripts

Bugsnag Notifier for Node.js

The Bugsnag Notifier for Node.js automatically notifies you of synchronous and asynchronous errors in your Node.js applications.

Bugsnag captures errors in real-time from your web, mobile and desktop applications, helping you to understand and resolve them as fast as possible. Create a free account to start capturing errors from your applications.

Install bugsnag using npm:

npm install bugsnag --save

Require bugsnag in your node.js app:

var bugsnag = require("bugsnag");

Register the bugsnag notifier with your API key:


See below for additional configuration options.

If your app uses Express or Connect, Bugsnag can automatically capture errors that happen during requests, including errors that happen in asynchronous code.

To ensure that asynchronous errors are routed to the error handler, add the requestHandler middleware to your app as the first middleware:


You'll also need to add Bugsnag's error handling middleware, make sure to add this after all other middleware, but before any "error" middleware:


If your app uses Restify, Bugsnag can automatically capture errors that happen during requests.

To get notified of the errors in your app, just add the Bugsnag restify handler to your code.

server.on("uncaughtException", bugsnag.restifyHandler);

If you don't use any other uncaughtException event listeners, you will need to add the default handler back in, like this.

server.on("uncaughtException", function (reqresroutee) {
  if (!res._headerSent) res.send(new restify.InternalError(e, e.message || 'unexpected error'));

If your app uses Koa, Bugsnag can automatically capture errors that happen during requests.

To get notified of the errors in your app, just add the Bugsnag koa handler to your code.

app.on("error", bugsnag.koaHandler)

When executing coffeecript code directly using the coffee executable, Bugsnag cannot notify about uncaught exceptions that occur at the top level of your app. This is due to a "feature" of the coffee executable.

To avoid this issue, make sure to compile your coffeescript files into javascript before running your app.

If you're using a promises library such as Bluebird or when.js, you can listen to unhandled promise rejections. See this document for more details.

process.on('unhandledRejection', function (errpromise) {
    console.error("Unhandled rejection: " + (err && err.stack || err));

To send non-fatal exceptions to Bugsnag, you can pass any Error object or string to the notify method:

bugsnag.notify(new Error("Non-fatal"));

You can also send additional meta data with your exception:

bugsnag.notify(new Error("Non-fatal"), {
  user: {
    username: "bob-hoskins",
    name: "Bob Hoskins",
    email: "bob@example.com"

You can set the severity of an error in Bugsnag by including the severity option when notifying bugsnag of the error,

bugsnag.notify(new Error("Non-fatal"), {
  severity: "error"

Valid severities are error, warning and info.

Severity is displayed in the dashboard and can be used to filter the error list. By default all crashes (or unhandled exceptions) are set to error and all bugsnag.notify calls default to warning.

See the full documentation for the notify function for more details.

Bugsnag can automatically capture both synchronous and asynchronous errors in your code if you wrap it in an autoNotify function. Note: If you are using the bugsnag.requestHandler middleware for Express or Connect, we automatically wrap your requests with autoNotify.

bugsnag.autoNotify(function() {
  // Your code here 

Additionally, you can pass options into autoNotify that will be used as default options for the notify call to any errors. See the notify docs for more details.

bugsnag.autoNotify({ context: "thisContext" }, function() {
  // Your code here 

The autoNotify function creates a Node.js Domain which automatically routes all uncaught errors to Bugsnag.

Many callback functions in Node are called with an error as the first argument. Bugsnag can intercept these errors if you wrap your callback with bugsnag.intercept:

functionWithCallback(bugsnag.intercept(function(argument) {
  // Your code here 

If the first argument is non-null, Bugsnag will be automatically notified of the error, and your callback will not be executed. The first argument is never passed to your callback, since it is assumed to be the error argument.

The bugsnag.register can accept an options object as its second parameter. The options can be a combination of any of the following:

By default, Bugsnag looks at the NODE_ENV environment variable to see what releaseStage the script is running in. If that is not set, Bugsnag assumes you are running in production. If you want to override this behavior, you can set the releaseStage option:

bugsnag.register("your-api-key-here", { releaseStage: "development" });

By default the notifier will notify Bugsnag of production and development exceptions. If you wish to be notified about production exceptions only, you can set the notifyReleaseStages option.

bugsnag.register("your-api-key-here", { notifyReleaseStages: ["production"] });

If you use an appVersion to identify releases of your app you can send it to Bugsnag. When set errors will only unresolve when they re-occur in a newer appVersion.

bugsnag.register("your-api-key-here", { appVersion: "1.0.0" });

Bugsnag will automatically register for the uncaughtexception event. If you do not wish for this to happen, you can disable the functionality as part of the register call:

bugsnag.register("your-api-key-here", { autoNotify: false });
### projectRoot

Bugsnag can highlight stacktrace lines that are in your project, and automatically hides stacktrace lines from external libraries. If Bugsnag is not hiding external stacktrace lines, it is likely that the projectRoot is being incorrectly calculated. You can set projectRoot as part of the register call:

bugsnag.register("your-api-key-here", { projectRoot: "/path/to/root" });

If the Bugsnag notifier is unable to locate your package.json, you can specify where to find it using packageJSON:

bugsnag.register("your-api-key-here", { packageJSON: "/path/to/package.json" });

By default, errors will be sent to Bugsnag using SSL. To disable SSL, you can set useSSL:

bugsnag.register("your-api-key-here", { useSSL: false });

By default, bugsnag will exit your application if there is an uncaught exception or an uncaught event emitter "error" event. This is in line with standard node.js behaviour. If you want to have different behaviour, then please set onUncaughtError as follows,

bugsnag.register("your-api-key-here", { onUncaughtErrorfunction(err){
  console.error(err.stack || err);

This function is called for all errors that aren't manually sent to bugsnag.notify. So a bugsnag.intercept call will trigger a call to onUncaughtError.

It is often very useful to send some extra application or user specific data along with every exception. To do this, you can set the metaData:

bugsnag.register("your-api-key-here", { metaData: {
  user: {
    username: "bob-hoskins",
    name: "Bob Hoskins",
    email: "bob@example.com"

You can adjust this after calling register by using the bugsnag.metaData property.

You can use a proxy server by configuring a proxy url when registering with bugsnag.

bugsnag.register("your-api-key-here", { proxy: "http://localhost:8080" });

You can prevent some meta-data keys (such as passwords) from being sent to Bugsnag by listing them in the filters. This is most useful if you're sending request data and don't want to accidentally log a user's password. The keys are matched with substring matching, so the default value of ["password"] also excludes things like "password_confirmation".

bugsnag.register("your-api-key-here", { filters: ["password", "creditcard"] }

By default we'll fetch the hostname using Node's os.hostname(), but you can override this as follows:

bugsnag.register("your-api-key-here", { hostname: "web1.example.com" }

If you want to modify error reports just before they are sent to Bugsnag, or prevent them from being sent, you can add before notify callbacks:

Bugsnag.onBeforeNotify(function (notification) {
    var metaData = notification.events[0].metaData;
    // modify meta-data 
    metaData.app = {version: '0.3'}
    // Don't log error reports from admins 
    if (metaData.user.is_admin) {
        return false;

You can add multiple beforeNotify callbacks, they'll be called in the order you add them.

If you want to send code snippets for each frame of the stacktrace you can enable sendCode. This asynchronously loads any file from the stacktrace, which is within the scope of the project, and sends 3 lines either side of the erroneous line of code to Bugsnag.

This works almost the same as how Bugsnag JavaScript projects handle sourcemaps - however loading the code is done on the local machine and sent over the internet with the error data.

bugsnag.register("your-api-key-here", { sendCode: true });

The bugsnag.notify function accepts an error as either a string or an Error object as the first argument, as well as options object as its second parameter. The options can be a combination of any of the following:

Errors in your Bugsnag dashboard are grouped by their "error class", to override the error class you can set errorName:

bugsnag.notify(new Error("Something went badly wrong"), { errorName: "BadError" });

A string representing what was happening in your application at the time of the error. In Express/Connect apps, this will automatically be set to the URL of the current request.

bugsnag.notify(new Error("Something went badly wrong"), { context: "/users/new" });

A unique identifier for a user affected by this error. This could be any distinct identifier that makes sense for your application. In Express/Connect apps, this is automatically set to the ip address of the current request.

bugsnag.notify(new Error("Something went badly wrong"), { userId: "bob-hoskins" });

If you need programmatical control over how the errors are grouped within bugsnag, you can send a groupingHash to the notify call. This will ensure that bugsnag groups all errors with the same groupingHash together.

bugsnag.notify(error, { groupingHash: "auth/create" });

Any extra data you want along with the exception report to Bugsnag. To do this just set other properties on the object, and you will see them as tabs in the error dashboard.

bugsnag.notify(new Error("Something went badly wrong"), {
  user: {
    username: "bob-hoskins",
    name: "Bob Hoskins",
    email: "bob@example.com"

You can set the severity of an error in Bugsnag by including the severity option when notifying bugsnag of the error,

bugsnag.notify(new Error("Non-fatal"), { 
  severity: "error"

Valid severities are error, warning and info.

Severity is displayed in the dashboard and can be used to filter the error list. By default all crashes (or unhandled exceptions) are set to error and all Bugsnag.notify calls default to warning.

A callback to call after notifying Bugsnag of an error. The callback has two arguments, err and response. The err argument will contain any error received when trying to send the notification, the response object will contain the response received from Bugsnag:

bugsnag.notify(new Error("Something went badly wrong"), function (errorresponse) {
  if(error) {
    // Something went wrong 
  } else {
    // The notify worked 

If you are using our express middleware, or otherwise using domains, you can set per-request metaData. This metaData will be sent with any crashes occurring during the current request.

bugsnag.requestData.user = {id: 5}

Please report any bugs or feature requests on the github issues page for this project here:


We love pull requests and issues. See CONTRIBUTING.md for instructions :).

The Bugsnag Node.js notifier is free software released under the MIT License. See LICENSE.txt for details.