What is Google Lighthouse?

Lighthouse is Google’s free, open-source tool that audits a web page and scores it out of 100 across performance, accessibility, best practices and SEO. It is the engine behind most speed reports you will see:

• It runs a single lab test - one simulated load on a set device and connection, then a scored report with specific, named fixes.
• It is built into Chrome - open DevTools (F12), click the Lighthouse tab, and run it on any page yourself, no account needed.
• It also powers PageSpeed Insights - which wraps the same Lighthouse audit alongside real-visitor field data.

Lighthouse is the most useful free diagnostic a small-business owner has, because it does not just grade you - it lists exactly what to fix. Run it on your homepage and your busiest page, and work down the opportunities it lists.