# Is postcss-custom-properties ESM-only? Can you require() it?

> postcss-custom-properties@15.0.1 is ESM-only. ESM-only since 15.0.0 — last CommonJS version is 14.0.6.

Use Custom Properties Queries in CSS

Last verified Sep 9, 2026 against postcss-custom-properties@15.0.1.

postcss-custom-properties dropped its CommonJS build in 15.0.0 (January 2026). The last version with a plain require()-able CommonJS entry is 14.0.6, published Jun 5, 2025; it declares support for Node.js >=18.

On Node.js 20.19+, 22.12+ and newer, require("postcss-custom-properties") works with the latest version: Node.js loads synchronous ES modules through require(). Verified on Node.js 20, 22, 24 and 26. Node.js 18 has no require(esm), and postcss-custom-properties@15.0.1 declares Node.js >=20.19.0, so 18 is outside its supported range anyway.

postcss-custom-properties@15.0.1 declares engines ">=20.19.0", so Node.js 18 is outside its supported range regardless of module format.

## What to do

1. On Node.js 20.19+, 22.12+ and newer, require("postcss-custom-properties") works with the latest version: Node.js loads synchronous ES modules through require(). Verified on Node.js 20, 22, 24 and 26.
2. From a CommonJS file, use a dynamic import inside an async function: const postcssCustomProperties = await import("postcss-custom-properties"). That works on every Node.js version the package supports (>=20.19.0).
3. If you need a synchronous require() or run Node.js 18: npm install postcss-custom-properties@14.0.6, the last CommonJS release (published Jun 5, 2025); it declares Node.js >=18.
4. postcss-custom-properties@15.0.1 declares engines ">=20.19.0", so Node.js 18 is unsupported regardless: upgrade Node.js or pin an older release.
5. TypeScript: types are bundled; install nothing extra.

## Facts

- Latest: 15.0.1 (Feb 21, 2026)
- Module format: ESM-only
- Last CommonJS version: 14.0.6
- ESM-only since: 15.0.0 (Jan 14, 2026)
- TypeScript types: bundled
- Node engines: >=20.19.0
- Weekly downloads: 6.8M
- License: MIT

## Runtime test results for postcss-custom-properties@15.0.1

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

| Runtime | require("postcss-custom-properties") | import "postcss-custom-properties" |
|---|---|---|
| Node.js 18 | fails (ERR_REQUIRE_ESM) | 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 postcss-custom-properties

ES modules:

```js
import * as postcssCustomProperties from "postcss-custom-properties";
```

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

CommonJS:

```js
// Node.js 20.19+, 22.12+ and newer (verified):
const postcssCustomProperties = require("postcss-custom-properties");

// Any Node.js version the package supports (>=20.19.0), from an async function:
async function main() {
  const postcssCustomProperties = await import("postcss-custom-properties");
}

// Or pin the last CommonJS release (declares Node.js >=18):
// npm install postcss-custom-properties@14.0.6
```

## Module format by version

Derived from the type, main and exports fields of every stable release on npm (96 versions; the newest 60 shown).

| Versions | Format | First published |
|---|---|---|
| 15.0.0 – 15.0.1 | ESM-only | Jan 14, 2026 |
| 12.1.0 – 14.0.6 | Dual (CommonJS + ESM) | Jan 12, 2022 |
| 12.0.1 – 12.0.4 | CommonJS | Dec 16, 2021 |
| 12.0.0 | Dual (CommonJS + ESM) | Sep 17, 2021 |
| 8.0.7 – 11.0.0 | CommonJS | Oct 2, 2018 |

## Frequently asked

**Is postcss-custom-properties ESM-only?**

postcss-custom-properties@15.0.1 is ESM-only. postcss-custom-properties dropped its CommonJS build in 15.0.0 (January 2026). The last version with a plain require()-able CommonJS entry is 14.0.6, published Jun 5, 2025; it declares support for Node.js >=18.

**Which version of postcss-custom-properties still supports CommonJS / require()?**

14.0.6 is the last version of postcss-custom-properties with a CommonJS build; it declares Node.js >=18. Install it with "npm install postcss-custom-properties@14.0.6". Every version from 15.0.0 on is ESM-only.

**How do I use postcss-custom-properties from a CommonJS file?**

From a CommonJS file, use a dynamic import inside an async function: const postcssCustomProperties = await import("postcss-custom-properties"). That works on every Node.js version the package supports (>=20.19.0). On Node.js 20.19+, 22.12+ and newer, require("postcss-custom-properties") works with the latest version: Node.js loads synchronous ES modules through require(). Verified on Node.js 20, 22, 24 and 26. Alternatively pin postcss-custom-properties@14.0.6 (declares Node.js >=18).

**Does postcss-custom-properties work in Bun?**

Yes. import "postcss-custom-properties" loaded successfully in Bun 1.4.0 on Sep 9, 2026.

**Does postcss-custom-properties ship TypeScript types?**

Yes. postcss-custom-properties bundles its own type declarations; no @types package is needed.

## Links

- [postcss-custom-properties on npm](https://www.npmjs.com/package/postcss-custom-properties)
- [Source repository](https://github.com/csstools/postcss-plugins)
- [HTML version](https://canirequire.com/package/postcss-custom-properties/)
- [JSON version](https://canirequire.com/package/postcss-custom-properties.json)

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