Page speed is a ranking factor on the margin. It's a huge factor for conversion. The two together make speed optimization one of the highest-leverage technical investments.
Core Web Vitals (covered in detail on its own page):
WebP or AVIF. Responsive srcset. Compressed. Lazy-loaded below fold. Proper width/height attributes. This alone can cut page weight 40-60% on image-heavy sites.
Minification (remove whitespace) + gzip/brotli compression at the server. Standard at this point; check it's actually enabled.
Load tracking, ads, chat widgets after the page is interactive:
<script defer src="..."></script>
<script async src="..."></script>The difference: defer preserves execution order; async runs whenever it loads (good for independent scripts).
<link rel="preload" href="/hero.webp" as="image">
<link rel="preload" href="/fonts/inter.woff2" as="font" type="font/woff2" crossorigin>Extract the CSS needed for above-the-fold rendering, inline it in the <head>. Load the rest async. Cuts LCP significantly.
Cloudflare, Fastly, AWS CloudFront. Geographically-distributed caching. Cuts latency for users far from your origin server.
Modern protocols multiplex requests and reduce handshake overhead. Most hosts support this by default now.
Audit what's loaded. Most sites have third-parties they don't need or use. Every one adds latency + is out of your control.
Cache-Control headersUse font-display: swap to render fallback text immediately. Self-host fonts (avoid Google Fonts latency) or use preconnect to the font CDN. Subset fonts to only the characters you need.
Ship those five and you'll beat 90% of competitors on speed.