SyntaxError: Cannot use import statement outside a module

Node.js · updated 2026-11-02

Thrown while Node parses a file, before any of it runs, when the file uses import or export but Node is treating it as CommonJS. Node decides per file: .mjs is ESM, .cjs is CommonJS, and .js follows the nearest package.json "type" field (CommonJS when it is missing). Test runners and TypeScript loaders add their own rules on top.

/srv/app/dist/server.js:1
import express from "express";
^^^^^^

SyntaxError: Cannot use import statement outside a module
    at internalCompileFunction (node:internal/vm:76:18)
    at wrapSafe (node:internal/modules/cjs/loader:1283:20)
    at Module._compile (node:internal/modules/cjs/loader:1328:27)

Quick fix

Decide which module system the package uses and make Node agree. For ESM, add "type": "module" to the package.json next to the file (or rename the file to .mjs). For CommonJS, compile the import statements away (TypeScript "module": "commonjs") or switch them to require(). The stack trace path shows which file Node treated as CommonJS.

Note the file in the first line of the error; that is the one Node parsed as CommonJS.
Find the nearest package.json above it and check its "type" field.
ESM project: set "type": "module", or use the .mjs extension for that file.
CommonJS project: make the build emit CommonJS (tsconfig "module": "commonjs") or use require().
Under Jest or ts-node, configure the transform or loader for ESM instead of changing app code.

json

{
  "name": "my-app",
  "type": "module",
  "scripts": { "start": "node dist/server.js" }
}

Why it happens

package.json has no "type": "module"

Without it, every .js file in the package is CommonJS, so the first import statement is a syntax error.

TypeScript emitted ESM into a CommonJS package

tsconfig "module": "esnext" (or "nodenext" with "type" unset) keeps import statements in dist/, which Node then loads as CommonJS.

A dependency ships ESM only and is loaded through a CommonJS path

Jest, ts-node and older bundlers transform your code but often not node_modules, so an ESM-only package fails inside the test or script runner.

Running a file from another package directory

Node uses the package.json nearest to the file, not the one in the working directory, so a script copied into a folder with its own package.json changes module type.

Other fixes

Pick one module system per package and set "type" explicitly either way.
For Jest, use its ESM support (NODE_OPTIONS=--experimental-vm-modules) or a transform that includes the ESM-only package.
Use .cjs and .mjs extensions for the odd file out instead of mixing styles in .js files.

Same error, other wording

SyntaxError: Unexpected token 'export'
Warning: To load an ES module, set "type": "module" in the package.json or use the .mjs extension.

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