Express

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

If you don't already have an account and a Sentry project established, sign up for Sentry for free, then return to this page.

Install

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.

npm install @sentry/node --save

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

Configure

Sentry should be initialized in your app as early as possible. It's essential that you call Sentry.init before you require any other modules in your application, otherwise, auto-instrumentation won't work for these modules.

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

To import and initialize Sentry, you'll need to create a file named instrument.js:

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,
});

Use

To ensure that Sentry can automatically instrument all modules in your application, you'll need to require or import the instrument.js file before requiring any other modules in your application:

// 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);

Add Readable Stack Traces to Errors

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

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

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.

Verify

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

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

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