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

> lightningcss@1.33.0 ships CommonJS and ESM builds. Dual package — require() works on every Node.js version we test; import works too.

A CSS parser, transformer, and minifier written in Rust

Last verified Sep 9, 2026 against lightningcss@1.33.0.

lightningcss publishes both a CommonJS entry and a native ESM entry (ESM added in 1.14.0). require("lightningcss") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. The package declares Node.js >= 12.0.0. import "lightningcss" works alongside it.

## What to do

1. Nothing to change. require("lightningcss") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. The package declares Node.js >= 12.0.0. import * as lightningcss from "lightningcss" works alongside it; use named imports for what the ESM entry exports.
2. TypeScript: types are bundled; install nothing extra.

## Facts

- Latest: 1.33.0 (Jul 20, 2026)
- Module format: Dual (CommonJS + ESM)
- Last CommonJS version: 1.33.0
- Native ESM since: 1.14.0
- TypeScript types: bundled
- Node engines: >= 12.0.0
- Weekly downloads: 128.6M
- License: MPL-2.0

## Runtime test results for lightningcss@1.33.0

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

| Runtime | require("lightningcss") | import "lightningcss" |
|---|---|---|
| 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 lightningcss

ES modules:

```js
import * as lightningcss from "lightningcss";
```

Namespace import shown because the ESM entry may have no default export; use named imports for what it exports.

CommonJS:

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

## Module format by version

Derived from the type, main and exports fields of every stable release on npm (43 versions; the newest 43 shown).

| Versions | Format | First published |
|---|---|---|
| 1.14.0 – 1.33.0 | Dual (CommonJS + ESM) | Sep 8, 2022 |
| 0.0.0 | CommonJS | Aug 22, 2022 |

## Frequently asked

**Is lightningcss ESM-only?**

lightningcss@1.33.0 ships CommonJS and ESM builds. lightningcss publishes both a CommonJS entry and a native ESM entry (ESM added in 1.14.0). require("lightningcss") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. The package declares Node.js >= 12.0.0. import "lightningcss" works alongside it.

**Can I require lightningcss?**

Yes. lightningcss ships a CommonJS entry alongside the native ESM entry. require("lightningcss") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. The package declares Node.js >= 12.0.0.

**Does lightningcss work in Bun?**

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

**Does lightningcss ship TypeScript types?**

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

## Links

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

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