useLightningcss
This feature is currently experimental and subject to change, it's not recommended for production. Try it out and share your feedback on GitHub.
Last updated October 9, 2025
Experimental support for using Lightning CSS with webpack. Lightning CSS is a fast CSS transformer and minifier, written in Rust.
If this option is not set, Next.js on webpack uses PostCSS with postcss-preset-env by default.
Turbopack uses Lightning CSS by default since Next 14.2. This configuration option has no effect on Turbopack. Turbopack always uses Lightning CSS.
next.config.ts
import type { NextConfig } from 'next' const nextConfig: NextConfig = { experimental: { useLightningcss: false, // default, ignored on Turbopack }, } export default nextConfigVersion History
| Version | Changes |
|---|---|
15.1.0 | Support for useSwcCss was removed from Turbopack. |
14.2.0 | Turbopack's default CSS processor was changed from @swc/css to Lightning CSS. useLightningcss became ignored on Turbopack, and a legacy experimental.turbo.useSwcCss option was added. |
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