Core Web Vitals and performance optimisation for headless Wix

One of the biggest advantages of going headless with Wix is the ability to achieve perfect Core Web Vitals scores. Without the standard Wix editor scripts and third-party widgets, you control every byte that loads on the page. This lesson covers the performance optimisation techniques that make headless sites rank higher.

LCP Optimisation: Sub-2.5 Second Loading

Largest Contentful Paint is often your hero image or main heading. On headless Wix, preload your hero image using a link rel="preload" tag, serve it from the Wix CDN with proper sizing parameters, and use fetchpriority="high" on the image element. For text-based LCP, ensure your web fonts load with font-display: swap and are preloaded.

CLS Prevention: Zero Layout Shift

Cumulative Layout Shift happens when elements load and push content around. On your headless frontend, set explicit width and height on all images using the dimensions from the Wix Media API, use CSS aspect-ratio for responsive containers, and ensure ads or dynamic content have reserved space.

INP Optimisation: Responsive Interactions

Interaction to Next Paint measures how quickly your page responds to user input. Minimise JavaScript bundle size by code-splitting per route, defer non-critical scripts, and use React Server Components or similar patterns to reduce client-side JavaScript.

Edge Caching and CDN Strategy

Deploy your headless frontend to an edge network like Vercel or Cloudflare Pages. This places your pre-rendered HTML on servers closest to your users globally. Combined with ISR, you get static-site speed with dynamic content freshness.

• Configure cache headers: immutable for static assets, s-maxage for ISR pages
• Use image CDN parameters from Wix Media for responsive images
• Implement service worker caching for repeat visitors
• Lazy load below-the-fold images and non-critical components
• Compress all responses with Brotli compression