Lighthouse bookmarklet

Jeremy Keith
1 min readMar 10, 2020

This was originally posted on my own site.

I use Firefox. You should too. It’s fast, secure, and more privacy-focused than the leading browser from the big G.

When it comes to web development, the CSS developer tooling in Firefox is second-to-none. But when it comes to JavaScript and network-related debugging (like service workers), Chrome’s tools are currently better than Firefox’s (for now). For example, Chrome has a tab in its developer tools that lets you run Lighthouse on the currently open tab.

Yesterday, I got the Calibre newsletter, which always has handy performance-related links from Karolina. She pointed to a Lighthouse extension for Firefox. “Excellent!”, I thought, and I immediately installed it. But I had some qualms about installing a plug-in from Google into a browser from Mozilla, particularly as the plug-in page says:

This is not a Recommended Extension. Make sure you trust it before installing

Well, I gave it a go. It turns out that all it actually does is redirect to the online version of Lighthouse. “Hang on”, I thought. “This could just be a bookmarklet!”

So I immediately uninstalled the browser extension and made this bookmarklet:

(You’ll need to go to the original blog post to grab the bookmarklet: Medium doesn’t like JavaScript URLs.)

Drag that up to your desktop browser’s bookmarks toolbar. Press it whenever you’re on a site that you want to test.

This was originally posted on my own site.

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Jeremy Keith

A web developer and author living and working in Brighton, England. Everything I post on Medium is a copy — the originals are on my own website, adactio.com