What is Render-Blocking Resource?
A script or stylesheet that delays first paint until it loads. Deferring non-critical JS, inlining critical CSS, and trimming third parties are the standard fixes.
Related terms
Page Speed
How fast a page becomes usable, measured by field metrics like LCP and INP rather than single lab scores. Small gains compound commercially: a tenth of a second has moved retail conversions measurably.
Largest Contentful Paint (LCP)
The Core Web Vital measuring when the main content element finishes rendering, ideally under 2.5 seconds. Hero images, web fonts, and slow server responses are the usual culprits.
Lazy Loading
Deferring below-the-fold images, video, and iframes until near the viewport. It trims initial page weight, the strongest lever on Core Web Vitals pass rates after server response.
Technical SEO
The crawling, indexing, rendering, and performance work that lets search engines reach, understand, and serve your pages. It covers directives, architecture, speed, and structured data rather than words on the page.
Crawling
How search-engine bots discover pages by following links, sitemaps, and directives. If a URL is never crawled, it cannot be indexed no matter how good its content is.
Crawl Budget
The number of pages a search engine will crawl on a site in a given period, driven by server capacity and demand signals. Large or slow sites must spend it on indexable, valuable URLs.