Website Performance Checklist for Modern Business Sites

Performance is a product decision. Slow sites leak trust before your headline finishes rendering.

Priority order

1. Server / TTFB — hosting, caching, edge
2. LCP element — usually hero image, video poster, or large heading stack
3. JavaScript weight — defer non-critical scripts
4. Fonts — subset, font-display, limit families
5. Images — modern formats, correct sizes, lazy-load below fold
6. Third parties — analytics, chat, embeds

Checklist

Delivery

• CDN / edge caching for static assets
• HTML cacheable where personalization allows
• Compression (Brotli/Gzip) enabled
• HTTP/2 or HTTP/3

Assets

• Hero image sized to display dimensions (not a 4000px source)
• AVIF/WebP with sensible fallbacks
• width/height or aspect-ratio to prevent CLS
• Lazy-load non-critical media only

JavaScript & CSS

• Critical CSS path kept lean
• Defer analytics until consent / idle where possible
• Avoid blocking third-party tag managers on first paint
• Code-split heavy routes

Fonts

• Self-host when possible
• Preload only the primary text face
• font-display: swap or optional
• Limit to 2–3 families max

Measurement

Use lab tools (Lighthouse, WebPageTest) and field data (CrUX / RUM). Lab-only wins that vanish on real mobile are not wins.

<link rel="preload" href="/fonts/syne.woff2" as="font" type="font/woff2" crossorigin />

FAQ