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

> undici-types@8.10.2 has no importable main entry. No JavaScript entry point.

A stand-alone types package for Undici

Last verified Sep 9, 2026 against undici-types@8.10.2.

undici-types does not expose a JavaScript entry point in package.json. It is likely a CLI, a stylesheet, a type-definition package, or an asset bundle, so require() and import are not the way to use it.

## What to do

1. Do not require() or import undici-types: it has no JavaScript entry point. Use it as a CLI (npx undici-types), a stylesheet, an asset, or a type-definition package as its README describes.
2. TypeScript: types are bundled; install nothing extra.

## Facts

- Latest: 8.10.2 (Sep 4, 2026)
- Module format: No JS entry point
- Last CommonJS version: n/a
- TypeScript types: bundled
- Node engines: not declared
- Weekly downloads: 284.0M
- License: MIT

## Runtime test results for undici-types@8.10.2

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

| Runtime | require("undici-types") | import "undici-types" |
|---|---|---|
| Node.js 18 | fails (MODULE_NOT_FOUND) | fails (ERR_MODULE_NOT_FOUND) |
| Node.js 20 | fails (MODULE_NOT_FOUND) | fails (ERR_MODULE_NOT_FOUND) |
| Node.js 22 | fails (MODULE_NOT_FOUND) | fails (ERR_MODULE_NOT_FOUND) |
| Node.js 24 | fails (MODULE_NOT_FOUND) | fails (ERR_MODULE_NOT_FOUND) |
| Node.js 26 | fails (MODULE_NOT_FOUND) | fails (ERR_MODULE_NOT_FOUND) |
| Bun 1.4.0 | fails (Error) | fails (Error) |

## How to import undici-types

ES modules:

```js
import * as undiciTypes from "undici-types";
```

## Module format by version

Derived from the type, main and exports fields of every stable release on npm (131 versions; the newest 60 shown).

| Versions | Format | First published |
|---|---|---|
| 7.2.2 – 8.10.2 | No JS entry point | Jan 15, 2025 |

## Frequently asked

**Is undici-types ESM-only?**

undici-types@8.10.2 has no importable main entry. undici-types does not expose a JavaScript entry point in package.json. It is likely a CLI, a stylesheet, a type-definition package, or an asset bundle, so require() and import are not the way to use it.

**Does undici-types work in Bun?**

Importing undici-types failed in Bun 1.4.0 on Sep 9, 2026: error: Cannot find package 'undici-types' from '/Users/boat/Projects/top-seo/data/probe-work/undici-types/imp.mjs'

**Does undici-types ship TypeScript types?**

Yes. undici-types bundles its own type declarations; no @types package is needed.

## Links

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

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