Hitting 95+ Core Web Vitals on a Commerce PWA

2025-06-12 Performance PWA SEO

Performance is mostly process. Enforce budgets, automate checks, and remove regressions fast.

Use import() for route‑level code‑splitting; prefetch rel=modulepreload for top journeys.
Ship AVIF/WebP and responsive images; serve critical CSS; avoid layout shift on price & CTA blocks.
Cache‑first for media; stale‑while‑revalidate for JSON; revalidate price/stock.

HTML <30KB, JS initial <90KB, CSS <40KB, Images <150KB above‑the‑fold