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Answer

How do you test a PWA with Lighthouse?

Short answer

Open Chrome DevTools, go to the Lighthouse panel, select the categories you want (Performance, PWA-related checks live under "Best Practices" in modern Lighthouse) and click "Analyze page load". Lighthouse reports whether your manifest is valid, whether a service worker is registered, and whether the page is served over HTTPS.

By InstantPWA engineering·Reviewed July 25, 2026

DevTools workflow

DevTools → Lighthouse tab → select device (mobile/desktop) → Analyze page load. Results include a report you can export as HTML or JSON.

CLI workflow

Install with npm install -g lighthouse, then run lighthouse https://example.com --view for the same report from the command line or CI.

What to check

The installability section under Application → Manifest in DevTools gives a more granular breakdown than Lighthouse alone if the install prompt is not firing.

Sources

Related
Why is my PWA install prompt not showing?
Chrome shows the install prompt only when the site passes strict installability criteria: HTTPS, a valid manifest with name, icons and start_url, a registered service worker with a fetch handler, and the user has not previously dismissed the prompt. Any one of these missing is enough to block the prompt entirely.
What are Core Web Vitals?
Core Web Vitals are three metrics Google uses to measure real-world page experience: Largest Contentful Paint (LCP, loading speed), Interaction to Next Paint (INP, responsiveness to input, which replaced First Input Delay in March 2024), and Cumulative Layout Shift (CLS, visual stability). They are measured from real Chrome users via the Chrome User Experience Report.
What is Workbox?
Workbox is a collection of open-source JavaScript libraries, maintained by Google, that wraps common service-worker patterns — precaching, runtime caching strategies, background sync, expiration — behind a simple API, so developers do not have to hand-write low-level Cache Storage and fetch-event logic.
What icon sizes does a PWA need?
A PWA manifest needs at least a 192x192 and a 512x512 icon to be installable on Chromium browsers. For best results across platforms, also include a maskable icon (so Android does not crop your logo oddly) and a separate 180x180 apple-touch-icon link for iOS Safari, which does not read the manifest for its home-screen icon.
Does a PWA need HTTPS?
Yes, a PWA needs HTTPS. Browsers refuse to register a service worker on a plain HTTP origin because it can intercept and modify every network request, which would be a serious security risk over an unencrypted connection. The only exception is localhost and 127.0.0.1, which browsers treat as a secure context for local development.