Web Development

Web Performance Checklist: Core Web Vitals for Marketing Sites

Analytics dashboard showing website performance metrics

Marketing sites built with modern frameworks can still miss Core Web Vitals if assets and rendering paths are not disciplined. Use this checklist before launch.

Largest Contentful Paint (LCP)

  • Preload hero image or critical font files.
  • Serve AVIF/WebP with responsive sizes.
  • Inline critical CSS for above-the-fold content.

Interaction to Next Paint (INP)

Break up long JavaScript tasks, defer non-critical scripts, and prefer CSS transitions over heavy scroll listeners on mobile.

Quick wins

  1. Audit third-party tags quarterly.
  2. Lazy-load below-the-fold media.
  3. Use a performance budget in CI.
Developer testing website speed on laptop
Measure on real devices—not only desktop emulation.

Cumulative Layout Shift (CLS)

Reserve space for images, ads, and dynamic banners. Avoid injecting UI above existing content after load.

Performance is a feature your SEO and conversion rates share.

Our web development team ships performance-first by default.