User can be prompted to install the web app

The prompt to install a web app lets users add your app to their homescreen. Users that add apps to homescreens engage those apps more. Learn more in Discover what it takes to be installable.

For example, shortly after launching this feature, Twitter reported an average of 250K unique daily users launching their Twitter Lite progressive web app 4 times a day from the homescreen. See Increasing engagement with "Add to Homescreen" prompt and web push notifications for more on Twitter's case study.

Lighthouse flags when your page is missing an installable manifest:

How this audit fails #

This audit fails when the following criteria isn't met:

• The web app is not already installed and prefer_related_applications is not true.
• Meets a user engagement heuristic (currently, the user has interacted with the domain for at least 30 seconds)
• Includes a web app manifest that includes:
  • short_name or name
  • icons must include a 192px and a 512px sized icons
  • start_url
  • display must be one of: fullscreen, standalone, or minimal-ui
• Served over HTTPS (required for service workers)
• Has registered a service worker with a fetch event handler

Recommendations #

In order for a user to be able to install your Progressive Web App, check that it meets the above criteria. When these criteria are met, the browser fires a beforeinstallprompt event that you can use to prompt the user to install your Progressive Web App, and may show a mini-info bar.

Other browsers have different criteria for installation, or to trigger the beforeinstallprompt event. Check their respective sites for full details: Edge, Firefox, Opera, Samsung Internet, and UC Browser.

In addition, the scope of the service worker includes the page you audited and the page specified in the start_url property of the web app manifest.

Learn more in Add a Web App Manifest.

More information #

User can be prompted to install web app audit source