Lighthouse Best Practices ScoreWhat it checks and how to fix it

What it checks

Reads the Best Practices category score from a Lighthouse run on the page, simulating a mid-range phone. A score of 90 or above passes, 50 to 89 warns, and below 50 fails. It runs on the pages chosen for Lighthouse.

Why it matters

The Best Practices score covers the health of the page itself: HTTPS everywhere, no errors in the browser console, no deprecated APIs or known-vulnerable libraries, correctly sized images and no intrusive permission prompts on load. A low score usually means real defects visitors can hit, and some of them, like mixed content or vulnerable libraries, are security risks.

How to fix it

Run Lighthouse in Chrome DevTools with the Best Practices category on mobile and work through the failing audits. The usual culprits:

• Console errors: open the DevTools console and fix the JavaScript errors and failed requests it lists.
• Mixed content: load every resource over HTTPS.
• Vulnerable or deprecated libraries: upgrade old jQuery, Bootstrap or other front-end dependencies.
• Images with the wrong aspect ratio or resolution: serve images at the size they are displayed, with width and height set.
• Permission prompts on load: ask for notifications or geolocation only after a user action.

<img src="/images/logo.webp" alt="Acme" width="160" height="40">

Aim for 90 or more and re-run Lighthouse after each change.