Make Next.js work offline
InstantPWA hosts a fallback service worker and manifest for Next.js, so pages you've already visited keep working offline without you writing cache logic yourself. Add the snippet to app/layout.tsx or pages/_document.tsx via root layout via next/script with strategy="afterInteractive" and the worker registers automatically on first visit.
Steps
- 1
Open app/layout.tsx or pages/_document.tsx
Go to root layout via next/script with strategy="afterInteractive".
- 2
Paste the InstantPWA snippet
Drop the one-line async script tag in the Next.js head section — no build step or dependency install.
- 3
Let the service worker register
No manifest.json or sw.js to write — InstantPWA serves both and scopes the worker to your site's root.
- 4
Test offline mode
Visit a page once, then use DevTools → Network → Offline (or airplane mode on a phone) and reload to confirm cached pages still render.
- 5
Verify on a phone
Open your live Next.js URL on a mobile device (not the editor preview) to confirm the popup renders.
Constraints to know
- App Router and Pages Router both work, but the script must be a Client Component boundary (next/script) — plain <script> tags inside a Server Component layout get stripped by React's hydration diffing.
- On Vercel Edge Middleware or strict CSP setups, add the InstantPWA domain to script-src or the snippet will be blocked silently.
FAQ
Do I need to write my own service worker?+
No — InstantPWA hosts a fallback manifest and service worker automatically if your site doesn't already ship one.
What happens to pages I haven't visited yet?+
They won't be available offline until visited at least once — InstantPWA caches on-visit rather than pre-caching your entire site.
Does offline mode change how Next.js serves pages normally?+
No — the service worker only intercepts requests when the browser is offline; online visits behave exactly as before.