Glossary
Core Web Vitals
Core Web Vitals are Google’s user-experience metrics — LCP, INP, and CLS — that measure loading, interactivity, and visual stability of a page.
Core Web Vitals are a set of user-centred performance metrics defined by Google to quantify real-world page experience. They feed into search ranking signals and reflect how a page actually feels to use.
The three metrics
- LCP (Largest Contentful Paint) — loading: how long until the main content appears. Good is under 2.5 s.
- INP (Interaction to Next Paint) — responsiveness to user input; replaced FID in 2024. Good is under 200 ms.
- CLS (Cumulative Layout Shift) — visual stability; how much the layout jumps. Good is under 0.1.
How hosting affects them
Server speed shows up directly in ttfb, which gates LCP. Enabling caching, gzip-brotli compression, a cdn, and http-2/http-3 all improve these scores.
Why it matters for hosting
Slow or distant hosting drags down LCP and INP. Choosing a fast host and the right performance stack is foundational to passing Core Web Vitals.
See also
TTFB (Time To First Byte)
TTFB measures how long after a request the first byte of the response arrives, reflecting server, network, and backend processing speed.
Caching
Caching stores copies of data or pages so repeat requests are served instantly, reducing server work and dramatically speeding up websites.
Gzip & Brotli Compression
Gzip and Brotli are HTTP compression methods that shrink text-based responses before sending, cutting transfer size and speeding up page loads.
CDN (Content Delivery Network)
A CDN is a worldwide network of edge servers that cache and serve your site close to visitors, cutting latency and absorbing traffic spikes.