Does not register a service worker that controls page and start_url

Registering a service worker is the first step towards enabling key Progressive Web App (PWA) features:

• Works offline
• Supports push notifications
• Can be installed to the device

Learn more in the Service workers and the Cache Storage API post.

Browser compatibility #

All major browsers except Internet Explorer support service workers. See Browser compatibility.

How the Lighthouse service worker audit fails #

Lighthouse flags pages that don't register a service worker:

Lighthouse checks if the Chrome Remote Debugging Protocol returns a service worker version. If it doesn't, the audit fails.

How to register a service worker #

Registering a service worker involves only a few lines of code, but the only reason you'd use a service worker is to make it possible to implement one of the PWA features outlined above. Actually implementing those features requires more work:

• To learn how to cache files for offline use, see the What is network reliability and how do you measure it? post.
• To learn how to make your app installable, see the Make it installable codelab.
• To learn how to enable push notifications, see Google's Adding Push Notifications to a Web App.

Resources #

• Source code for Does not register a service worker that controls page and start_url audit
• Service Workers: an Introduction
• Service workers and the Cache Storage API
• What is network reliability and how do you measure it?
• Make it installable
• Adding Push Notifications to a Web App