Project - Remove unused CSS from modern web applications

Overview

PurgeCSS is a build-time utility designed to eliminate unused CSS from web projects. Many modern applications rely on large CSS frameworks like Tailwind, Bootstrap, or Materialize, which generate vast numbers of possible selectors — most of which are not used in a given project. PurgeCSS analyzes your project’s source files and your CSS files, matches the selectors used in content with those defined in stylesheets, and removes selectors that aren’t referenced. The result is a leaner final CSS bundle optimized for production.

The tool can be integrated into a range of workflows. It offers a programmatic JavaScript API, a CLI, and plugins for common build tools like PostCSS, Webpack, Gulp, and Rollup. You specify the files to analyze — including HTML, JS, or framework-specific files — and PurgeCSS computes which CSS rules are truly needed. Configuration options allow fine-tuning through extractors and safelists to handle custom selector patterns or avoid removing CSS that is required at runtime.

PurgeCSS is commonly used in production build pipelines to keep CSS payloads small, reducing the amount of CSS that must be downloaded and parsed by browsers. The smaller stylesheet size can meaningfully improve page load times, especially in large applications or those using utility-first frameworks.

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