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Tim Neutkens bccf4bbfbd
Add @tailwindcss/webpack loader for Tailwind CSS v4 (#19610)
## Summary

This PR adds a new `@tailwindcss/webpack` package that provides a
dedicated webpack loader for Tailwind CSS v4. This loader works with
both standard webpack and Turbopack's webpack loader compatibility
layer.

### Why a dedicated loader?

The current webpack integration uses `postcss-loader` +
`@tailwindcss/postcss`. While this works, a dedicated loader:

- **Eliminates PostCSS as a middleman** - works directly with CSS
strings (no AST conversions)
- **Simpler and more efficient** - follows the same pattern as
`@tailwindcss/vite`
- **Better for Turbopack** - gives direct control over dependency
reporting via webpack's loader API

### How it works

The loader mirrors the Vite plugin's approach:

1. Uses `compile()` from `@tailwindcss/node` to parse CSS and resolve
`@apply` directives
2. Uses `Scanner` from `@tailwindcss/oxide` to scan content files for
utility candidates
3. Reports dependencies via `this.addDependency()` and
`this.addContextDependency()`
4. Optionally optimizes output with Lightning CSS

### Usage

```javascript
// webpack.config.js
module.exports = {
  module: {
    rules: [
      {
        test: /.css$/i,
        use: [
          MiniCssExtractPlugin.loader,
          'css-loader',
          '@tailwindcss/webpack',  // No PostCSS needed!
        ],
      },
    ],
  },
}
```

### Options

- `base` - The base directory to scan for class candidates (defaults to
`process.cwd()`)
- `optimize` - Whether to optimize/minify the output CSS (defaults to
`true` in production)

### Files added

- `packages/@tailwindcss-webpack/` - New package
  - `src/index.ts` - Main loader implementation
  - `src/index.cts` - CommonJS entry point for webpack compatibility
  - `package.json`, `tsconfig.json`, `tsup.config.ts`, `README.md`
- `integrations/webpack/loader.test.ts` - Integration tests
- `integrations/utils.ts` - Added webpack override for transitive
dependencies

### Test plan

- [x] Build test - verifies basic compilation
- [x] Watch test - verifies HMR when adding new Tailwind classes
- [x] `@apply` test - verifies `@apply` directives work correctly
- [x] Optimization test - verifies minification works

---------

Co-authored-by: Robin Malfait <malfait.robin@gmail.com>
2026-01-29 14:16:31 +00:00
.github Revert "temporarily disable discord notifications" 2026-01-06 16:40:50 +01:00
crates pin @napi-rs/cli 2026-01-06 15:19:59 +01:00
integrations Add @tailwindcss/webpack loader for Tailwind CSS v4 (#19610) 2026-01-29 14:16:31 +00:00
packages Add @tailwindcss/webpack loader for Tailwind CSS v4 (#19610) 2026-01-29 14:16:31 +00:00
patches Update Lightning CSS to 1.30.2 (#19143) 2025-10-17 15:41:49 -04:00
playgrounds Update bun 1.3.3 → 1.3.5 (patch) (#19489) 2025-12-24 17:20:02 -05:00
scripts Make TypeScript a bit more happy (#19124) 2025-10-14 19:52:46 +00:00
.gitignore Fix slow unit test (#17465) 2025-03-31 15:26:01 +02:00
.prettierignore Hoist oxide/crates to just crates (#13333) 2024-03-23 09:00:48 -04:00
Cargo.lock Remove unused crossbeam dependency in oxide (#19256) 2025-11-04 10:37:21 -05:00
Cargo.toml Hoist oxide/crates to just crates (#13333) 2024-03-23 09:00:48 -04:00
CHANGELOG.md Add @tailwindcss/webpack loader for Tailwind CSS v4 (#19610) 2026-01-29 14:16:31 +00:00
LICENSE Add README, LICENSE, and CONTRIBUTING (#13088) 2024-03-05 14:45:39 -05:00
package.json Revert "retry integration tests 3 times before actually failing" 2026-01-06 16:23:46 +01:00
pnpm-lock.yaml Add @tailwindcss/webpack loader for Tailwind CSS v4 (#19610) 2026-01-29 14:16:31 +00:00
pnpm-workspace.yaml Add @tailwindcss/webpack loader for Tailwind CSS v4 (#19610) 2026-01-29 14:16:31 +00:00
README.md Update README.md (#18434) 2025-07-02 16:40:30 -04:00
rust-toolchain.toml Improve Oxide candidate extractor [0] (#16306) 2025-03-05 11:55:24 +01:00
turbo.json Fix segmentation fault when loading @tailwindcss/oxide in a Worker thread (#17276) 2025-03-18 16:28:20 -04:00
vitest.config.ts Bump Vitest to v4 (#19216) 2025-11-20 18:16:20 -05:00

Tailwind CSS

A utility-first CSS framework for rapidly building custom user interfaces.

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Documentation

For full documentation, visit tailwindcss.com.

Community

For help, discussion about best practices, or feature ideas:

Discuss Tailwind CSS on GitHub

Contributing

If you're interested in contributing to Tailwind CSS, please read our contributing docs before submitting a pull request.