# Is mz ESM-only? Can you require() it?

> mz@2.7.0 is a CommonJS package. CommonJS — require() works on every Node.js version we test.

modernize node.js to current ECMAScript standards

Last verified Sep 9, 2026 against mz@2.7.0.

mz ships CommonJS only. require("mz") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. import "mz" also works because Node.js and Bun can import CommonJS from ES modules, but only the default export is guaranteed; named imports depend on Node's static analysis of the module.

## What to do

1. require("mz") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun.
2. From ES modules use the default import: import mz from "mz"; then destructure. Named imports only work when Node.js can statically detect the exports.
3. TypeScript: npm install -D @types/mz

## Facts

- Latest: 2.7.0 (Sep 13, 2017)
- Module format: CommonJS
- Last CommonJS version: 2.7.0
- TypeScript types: @types/mz
- Node engines: not declared
- Weekly downloads: 48.1M
- License: MIT

## Runtime test results for mz@2.7.0

Installed and executed on Sep 9, 2026 with require("mz") from a CommonJS file and import "mz" from an ES module.

| Runtime | require("mz") | import "mz" |
|---|---|---|
| Node.js 18 | works | works |
| Node.js 20 | works | works |
| Node.js 22 | works | works |
| Node.js 24 | works | works |
| Node.js 26 | works | works |
| Bun 1.4.0 | works | works |

## How to import mz

ES modules:

```js
import mz from "mz";
```

CommonJS:

```js
const mz = require("mz");
```

## Module format by version

Derived from the type, main and exports fields of every stable release on npm (22 versions; the newest 22 shown).

| Versions | Format | First published |
|---|---|---|
| 0.1.1 – 2.7.0 | CommonJS | May 8, 2014 |

## Frequently asked

**Is mz ESM-only?**

mz@2.7.0 is a CommonJS package. mz ships CommonJS only. require("mz") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. import "mz" also works because Node.js and Bun can import CommonJS from ES modules, but only the default export is guaranteed; named imports depend on Node's static analysis of the module.

**Can I import mz with ES module syntax?**

Yes. import mz from "mz" works in Node.js and Bun because they support importing CommonJS modules. Named imports work only when Node.js can statically detect the exports.

**Does mz work in Bun?**

Yes. import "mz" loaded successfully in Bun 1.4.0 on Sep 9, 2026.

**Does mz ship TypeScript types?**

Not bundled. Install the community types with "npm install -D @types/mz".

## Links

- [mz on npm](https://www.npmjs.com/package/mz)
- [Source repository](https://github.com/normalize/mz)
- [HTML version](https://canirequire.com/package/mz/)
- [JSON version](https://canirequire.com/package/mz.json)

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