css-charset-webpack-plugin

css-charset-webpack-plugin is a plugin that makes sure every generated CSS file starts with a valid @charset rule, so browsers can correctly detect the file’s character encoding (usually utf-8).

If you find this plugin useful for your projects, please consider supporting me by Github, Patreon, KO-FI or Paypal. It's a great way to help me maintain and improve this tool in the future. Your support is truly appreciated!

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✨ Features

• ✅ Adds a valid @charset rule at the very top of every CSS file.
• ✅ Removes any duplicate or misplaced @charset rules for spec compliance.
• ✅ Works with Webpack 4, Webpack 5, and Rspack.
• ✅ Supports both CommonJS and ES Modules.

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📦 Installation

npm install css-charset-webpack-plugin --save-dev

🚀 Usage

CommonJS (webpack.config.js / rspack.config.js)

const CssCharsetPlugin = require('css-charset-webpack-plugin');

module.exports = {
    plugins: [
        new CssCharsetPlugin({
            charset: 'utf-8',
        })
    ]
};

ES Modules (webpack.config.mjs / rspack.config.mjs)

import CssCharsetPlugin from 'css-charset-webpack-plugin';

export default {
    plugins: [
        new CssCharsetPlugin({
            charset: 'utf-8',
        })
    ]
};

📝 Output Example

After build, all CSS files will automatically include the @charset declaration at the top:

@charset "utf-8";

html {
  margin: 0;
  padding: 0;
}

⚙️ Options

Name	Type	Default	Description
charset	string	utf-8	Character encoding to prepend. Usually set to utf-8 for maximum compatibility.

📌 Note

According to the CSS specification,

• Only the very first @charset rule at the top of the file is valid.
• Any additional @charset rules are ignored by browsers and may cause compatibility issues. 👉 For safety, all existing @charset rules in the CSS file will be removed before prepending the new one.

📄 License

MIT © 2025 Nguyen Ngoc Long