Tốc độ & Core Web Vitals

Why milliseconds matter

Visitors abandon pages that take more than a few seconds, and search engines fold page-experience metrics (Google's Core Web Vitals) into ranking. Speed also controls crawl efficiency: a slow server gets crawled less, so changes take longer to be noticed. AI crawlers time out on slow pages the same way people do.

The big levers, in order: server response time (TTFB), text compression, HTTP/2 or newer, render-blocking scripts, and image weight.

What this site measures

TTFB from our server (a lab measurement, labeled as such), HTML document size, the number of referenced resources, render-blocking scripts in the head, and modern image delivery (WebP/AVIF, lazy loading). Google's free PageSpeed Insights adds field data from real Chrome visitors; the two views complement each other.

How to improve

• Get server response under ~300 ms with caching or a CDN.
• Enable gzip or Brotli compression and HTTP/2 on the server, usually one setting.
• Add defer or async to every script that isn't needed for first paint.
• Serve images as WebP/AVIF, sized to their containers, with loading="lazy".
• Audit third-party tags ruthlessly; each one is someone else's slow server.

Common mistakes

A dozen marketing pixels loaded synchronously in the head. Hero images shipped at 4000px width. Cheap shared hosting with 2-second TTFB under real traffic. Measuring once on office wifi and calling it fast.