Minification reduces file size by stripping whitespace, comments, and unneeded characters from CSS,
JavaScript, and HTML. Smaller files transfer faster, especially on slower networks, and help improve
metrics like Time to First Byte (TTFB proxy), First Contentful Paint (FCP), and Largest Contentful Paint
(LCP). When combined with proper caching, minification helps push repeat views closer to instant, as the
browser needs to download less on first load and can reuse the smaller assets across pages.
Deferring JavaScript is particularly impactful: it tells the browser to prioritize parsing and rendering
document content before executing non‑critical scripts. This reduces main‑thread blocking during the
initial render, leading to earlier visual completeness. That said, not every script is safe to defer.
Some libraries expect to run early, set up globals, or initialize layout‑critical interactions. WP
Lightning Load includes an option to skip deferring jQuery to preserve compatibility with older themes
or plugins that rely on its early availability. If you enable defer and notice broken menus, sliders, or
forms, exclude the offending files from processing or temporarily disable defer to isolate the issue.
HTML minification can yield modest gains but is generally safe. Always test after enabling CSS/JS/HTML
minify and defer. Start with HTML minify, then CSS minify, then JS minify, and finally defer. This
staged approach makes it easy to pinpoint problems. With careful configuration, minification and defer
provide a reliable boost without sacrificing functionality.