Service worker is configured for repeat visit caching

Service workers enable the browser to serve cached assets without hitting the network on repeat visits — a capability that directly reduces ISO-25010 resource-utilisation for returning users. Marketing pages attract a significant proportion of return visitors from email campaigns, social retargeting, and direct traffic, yet without a service worker those visitors re-download every JavaScript bundle, CSS file, and image on each visit as if they've never been to the site. On an 800KB page, that's approximately 400ms of avoidable latency on 4G. Service worker caching also enables offline-capable page loads, which improves perceived reliability and supports scenarios like email campaigns opened in low-signal environments.

Add next-pwa for zero-configuration service worker caching in Next.js — it caches static assets and pages automatically based on build output.

npm install next-pwa

// next.config.ts
import withPWA from 'next-pwa'

export default withPWA({
  dest: 'public',
  disable: process.env.NODE_ENV === 'development',
  // Automatically caches JS chunks, CSS, and static images
})({
  // ...your existing Next.js config
})

Verify the service worker is registered by opening Chrome DevTools → Application → Service Workers after a production build. For non-Next.js projects, use Workbox directly: npm install --save-dev workbox-cli && npx workbox generateSW workbox-config.js.