Minification.

Minification is the process of removing all non-essential characters from source code files — CSS, JavaScript, and HTML — without changing their functionality. This includes stripping whitespace, line breaks, comments, unused code, and shortening variable names in JavaScript. The result is smaller file sizes that download faster over the network. A typical JavaScript file can be reduced by 20–60% through minification alone.

Minification in the Page Speed Stack

Minification is one layer of a broader performance optimisation stack that also includes compression (Gzip/Brotli, which further reduces transfer size), code splitting (only loading JavaScript needed for the current page), tree shaking (removing unused code from JavaScript bundles), and caching (avoiding repeated downloads). Minification typically happens as part of a build process — webpack, Vite, esbuild, or Parcel handle it automatically for modern JavaScript applications.

SEO Relevance

Google's PageSpeed Insights and Lighthouse audit for minification of CSS, JavaScript, and HTML, showing estimated byte savings. Reducing file sizes improves TTFB and LCP — particularly impactful for mobile users on slower connections. Most web frameworks and CDNs now handle minification automatically, but legacy sites built on WordPress or custom CMS platforms may require plugins (WP Rocket, NitroPack) or manual build process updates to enable it.