CssMinimizerWebpackPlugin

8.0.0 verified Sat Apr 25 auth: no javascript

Webpack plugin that minifies CSS using cssnano, with optional support for csso, clean-css, esbuild, and swc. Current stable version is 8.0.0, released 2026-03-02, requiring Node.js >= 20.9.0 and Webpack ^5. Unlike optimize-css-assets-webpack-plugin, it offers better source map handling, caching, and parallel processing via worker threads. Release cadence is roughly annual with patch releases for bug fixes. Ships TypeScript types.

Common errors

error Error: CssMinimizerPlugin is not a constructor ↓

cause Using named import (import { CssMinimizerPlugin }) in CommonJS or incorrect import style.

fix

Use default import: import CssMinimizerPlugin from 'css-minimizer-webpack-plugin' or const CssMinimizerPlugin = require('css-minimizer-webpack-plugin').default

error Module not found: Error: Can't resolve 'css-minimizer-webpack-plugin' ↓

cause Package not installed or in devDependencies.

fix

Run 'npm install --save-dev css-minimizer-webpack-plugin'

error TypeError: Cannot read properties of undefined (reading 'tapAsync') ↓

cause Webpack version < 5 is used, or mismatched plugin version.

fix

Ensure Webpack >= 5 is installed and compatible plugin version.

Warnings

breaking Minimum supported Node.js version is 20.9.0 starting from v8.0.0. ↓

fix Upgrade Node.js to version >= 20.9.0.

breaking Minimum supported Node.js version is 18.12.0 starting from v6.0.0. ↓

fix Upgrade Node.js to version >= 18.12.0.

breaking Updated cssnano to v7 in v7.0.0; cssnano v7 has breaking changes. ↓

fix Review cssnano v7 migration guide: https://github.com/cssnano/cssnano/releases/tag/cssnano%406.0.0

breaking Updated cssnano to v6 in v5.0.0; cssnano v6 has breaking changes. ↓

fix Review cssnano v6 migration guide: https://github.com/cssnano/cssnano/releases/tag/cssnano%406.0.0

gotcha Source maps only work with source-map, inline-source-map, hidden-source-map, or nosources-source-map devtool values. ↓

fix Set devtool to one of the supported values (e.g., 'source-map').

Install

npm install css-minimizer-webpack-plugin

yarn add css-minimizer-webpack-plugin

pnpm add css-minimizer-webpack-plugin

Imports

CssMinimizerPlugin
wrong
```
import CssMinimizerPlugin from 'css-minimizer-webpack-plugin';
```
correct
```
const CssMinimizerPlugin = require('css-minimizer-webpack-plugin');
```
CommonJS default export. ESM import (import CssMinimizerPlugin) also works in Node >= 18 with package.json type:module, but TypeScript users must use esModuleInterop or default import.

typeof CssMinimizerPlugin

wrong

import CssMinimizerPluginOptions from 'css-minimizer-webpack-plugin';

correct

import type { CssMinimizerPluginOptions } from 'css-minimizer-webpack-plugin';

TypeScript users should import the options type separately; the plugin itself is a class, not a type.

Quickstart

Basic webpack configuration integrating CssMinimizerPlugin with MiniCssExtractPlugin for CSS minification in production.

const CssMinimizerPlugin = require('css-minimizer-webpack-plugin');
const MiniCssExtractPlugin = require('mini-css-extract-plugin');

module.exports = {
  module: {
    rules: [
      {
        test: /\.css$/,
        use: [MiniCssExtractPlugin.loader, 'css-loader'],
      },
    ],
  },
  optimization: {
    minimizer: [
      new CssMinimizerPlugin(),
    ],
  },
  plugins: [new MiniCssExtractPlugin()],
};