Core Web Vitals
Core Web Vitals — Google's LCP, INP, and CLS metrics — measure real rendered pages, not XML feed files directly, but a bloated or uncached RSS feed can still drag down site performance by straining shared server resources. This tag gathers PostRSS's technical articles on the real relationship between RSS feed size, caching, and page speed, including practical fixes like item-count limits, excerpts, and proper cache headers. Read here if you're trying to separate feed myths from the actual mechanisms that affect your site's speed scores. The short version is that the feed file itself is not measured, but a feed serving hundreds of full articles on every request competes for the same resources as the page that is. Limiting item counts and serving cache headers fixes most of it.
Updated: 2026-09-27
Short answer: no, and yes. Google's Core Web Vitals are measured on rendered HTML pages — your homepage, your blog posts, your ...
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