Express

Learn about using Sentry with Express.

This guide explains how to set up Sentry in your Express application.

Don't already have an account and Sentry project established? Head over to sentry.io, then return to this page.

In addition to capturing errors, you can monitor interactions between multiple services or applications by enabling tracing. You can also collect and analyze performance profiles from real users with profiling.

Select which Sentry features you'd like to install in addition to Error Monitoring to get the corresponding installation and configuration instructions below.

Sentry captures data by using an SDK within your application’s runtime.

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npm install @sentry/node @sentry/profiling-node --save

Sentry should be initialized as early in your app as possible. It is essential that you call Sentry.init before you require any other modules in your application—otherwise, auto-instrumentation of these modules will not work.

Once this is done, Sentry's Node SDK captures unhandled exceptions as well as tracing data for your application.

You need to create a file named instrument.js that imports and initializes Sentry:

instrument.js
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const Sentry = require("@sentry/node");
const { nodeProfilingIntegration } = require("@sentry/profiling-node");

// Ensure to call this before requiring any other modules!
Sentry.init({
  dsn: "https://examplePublicKey@o0.ingest.sentry.io/0",
  integrations: [
    // Add our Profiling integration
    nodeProfilingIntegration(),
  ],

  // Add Tracing by setting tracesSampleRate
  // We recommend adjusting this value in production
  tracesSampleRate: 1.0,

  // Set sampling rate for profiling
  // This is relative to tracesSampleRate
  profilesSampleRate: 1.0,
});

Once you set a tracesSampleRate, performance instrumentation is automatically enabled for you. See Automatic Instrumentation to learn about all the things that the SDK automatically instruments for you.

You can also manually capture performance data - see Custom Instrumentation for details.

You need to require or import the instrument.js file before requiring any other modules in your application. This is necessary to ensure that Sentry can automatically instrument all modules in your application:

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// Require this first!
require("./instrument");

// Now require other modules
const express = require("express");
const Sentry = require("@sentry/node");

const app = express();

// Add your routes, etc.

// Add this after all routes,
// but before any and other error-handling middlewares are defined
Sentry.setupExpressErrorHandler(app);

app.listen(3000);

Depending on how you've set up your project, the stack traces in your Sentry errors probably don't look like your actual code.

To fix this, upload your source maps to Sentry. The easiest way to do this is to use the Sentry Wizard:

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npx @sentry/wizard@latest -i sourcemaps

The wizard will guide you through the following steps:

  • Logging into Sentry and selecting a project
  • Installing the necessary Sentry packages
  • Configuring your build tool to generate and upload source maps
  • Configuring your CI to upload source maps

For more information on source maps or for more options to upload them, head over to our Source Maps documentation.

This snippet includes an intentional error, so you can test that everything is working as soon as you set it up.

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app.get("/debug-sentry", function mainHandler(req, res) {
  throw new Error("My first Sentry error!");
});

Learn more about manually capturing an error or message in our Usage documentation.

To view and resolve the recorded error, log into sentry.io and open your project. Clicking on the error's title will open a page where you can see detailed information and mark it as resolved.

Help improve this content
Our documentation is open source and available on GitHub. Your contributions are welcome, whether fixing a typo (drat!) or suggesting an update ("yeah, this would be better").