Every Joomla template ships the full Bootstrap stylesheet — about 223 KB of CSS — while a typical site uses a fraction of it. VP Speed rebuilds Bootstrap from the official Sass sources with only the modules and components you select. A minimal grid-and-buttons setup compiles to around 21 KB: 90% less render-blocking CSS on the most important request of the page.
The compiled bundle replaces the full Bootstrap automatically — whether your template loads it through the Web Asset Manager, the legacy API, or a hardcoded link. Compilation happens once, when you save the settings, never on a live page view.
On the JavaScript side, VP Speed defers external scripts so they stop blocking the first paint, and the Pro edition can delay scripts until the visitor's first interaction — analytics, chat widgets and pixels simply stay out of the way of your Largest Contentful Paint. Add resource preloading and one-click browser caching, and the usual red PageSpeed audits start turning green.
