Test a PWA

In one line: Chrome DevTools’ Application panel lets you inspect, modify, and debug web app manifests, service workers, and service worker caches — the manifest’s Installability section flags what is blocking installation, and the Service Workers tab’s Offline checkbox lets you simulate offline conditions without disconnecting your machine.

1. Inspect the manifest

Open DevTools’ Application panel and select the Manifest tab. It shows the Identity and Presentation fields from your manifest source in a more readable form, the icons you have declared, and any registered shortcuts and screenshots. Per Chrome for Developers, if DevTools encounters an error — such as an icon that cannot be loaded — the Manifest tab displays an Installability section describing the error.

When you trigger installation from the address bar’s Install button, keep the Console drawer open: per Chrome for Developers, the Console reports issues with your manifest and logs other information about the installation process.

{
  "name": "Example PWA",
  "start_url": "/",
  "display": "standalone",
  "icons": [{ "src": "/icon-512.png", "sizes": "512x512", "type": "image/png" }]
}

2. Where this tooling is supported

The Application panel’s Manifest and Service Workers tabs described here are a Chrome DevTools feature. For the underlying APIs’ own browser support — independent of which devtools you use to inspect them — see the Service Workers compatibility table on this site.

3. Test the service worker with the Service Workers tab

If a service worker is installed for the currently open page, it is listed on the Service Workers tab. From there, per Chrome for Developers:

• The Offline checkbox puts DevTools into offline mode, equivalent to the offline mode available from the Network panel.
• The Update on reload checkbox forces the service worker to update on every page load.
• The Bypass for network checkbox bypasses the service worker and forces the browser to go to the network for requested resources.
• The Push button emulates a push notification without a payload, and the Sync button emulates a background sync event.
• Explicitly stopping the service worker with the stop link simulates the browser stopping it, which Chrome for Developers notes “frequently reveals bugs due to faulty assumptions about persistent global state.”

4. Detect whether a service worker is registered for the page

Per MDN, navigator.serviceWorker is undefined in browsers that lack Service Worker support, and ServiceWorkerContainer.getRegistration() resolves with undefined when no registration is found for the given scope. Checking both before assuming a registration exists keeps the test from throwing in a browser that lacks the API:

async function isPwaTestable() {
  if (!('serviceWorker' in navigator)) {
    return { testable: false, reason: 'Service workers are not supported in this browser.' };
  }
  const registration = await navigator.serviceWorker.getRegistration();
  if (!registration) {
    return { testable: false, reason: 'No service worker is registered for this page yet.' };
  }
  return { testable: true, registration };
}

Practical checklist

• PWA-specific auditing in Lighthouse is deprecated: Chrome for Developers’ own docs carry the notice “PWA testing in Lighthouse is deprecated,” and point instead to Chrome’s installability criteria and the DevTools Application panel for current guidance — do not rely on a Lighthouse PWA score as your test.
• The Install app / Add to home screen entry point in desktop Chrome cannot simulate the mobile install workflow; per Chrome for Developers, testing the genuine mobile experience requires a real device connected over remote debugging.
• Stopping a service worker from the Service Workers tab is a deliberate way to exercise restart behavior — do it before shipping, since production browsers stop and restart service workers on their own schedule, not just when you reload the page.
• The Update Cycle table on the Service Workers tab shows the service worker’s activities and their elapsed times, such as install, wait, and activate.

Where to go next

See What a service worker is, and the smallest one that works for what the Update Cycle table in the Service Workers tab is measuring, and Service Workers for browser support of the API this guide’s tests exercise.