ESM (MJS)

When running your application in ESM mode, you can't use require() to load modules. Instead, you have to use the --import command line options to load a module before the application starts.

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

import * as Sentry from "@sentry/node";

// Ensure to call this before importing any other modules!
Sentry.init({
  dsn: "https://examplePublicKey@o0.ingest.sentry.io/0",

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

Adjust the Node.js call for your application to use the --import parameter and point it at instrument.js, which contains your Sentry.init() code:

# Note: This is only available for Node v18.19.0 onwards.
node --import ./instrument.mjs app.mjs

If it is not possible for you to pass the --import flag to the Node.js binary, you can alternatively use the NODE_OPTIONS environment variable as follows:

NODE_OPTIONS="--import ./instrument.mjs" npm run start

We do not support ESM in Node versions before 18.19.0.

Troubleshooting instrumentation

By default, all packages are wrapped under the hood by import-in-the-middle to aid instrumenting them.

If import-in-the-middle encounters problems wrapping a package, you may see syntax errors at runtime or logged errors in your console:

SyntaxError: The requested module '...' does not provide an export named '...'
(node:3368) Error: 'import-in-the-middle' failed to wrap 'file://../../path/to/file.js'

To confirm that these errors are caused by import-in-the-middle, disable it by setting registerEsmLoaderHooks to false. Note, this will also disable tracing instrumentation:

import * as Sentry from "@sentry/node";

Sentry.init({
  registerEsmLoaderHooks: false,
});

If you are starting Sentry via --import, you can instruct import-in-the-middle to only wrap packages that Sentry specifically instruments. To do this, you can set the onlyIncludeInstrumentedModules to true:

import * as Sentry from "@sentry/node";

Sentry.init({
  registerEsmLoaderHooks: {
    onlyIncludeInstrumentedModules: true,
  },
});