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Lighthouse is an open-source, automated tool for improving the quality of web pages. It runs a series of audits against a URL and generates a report covering performance, accessibility, SEO, and best practices. Results are never sent to a remote server — all analysis happens locally using a Chrome instance on your machine.

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What Lighthouse measures

Lighthouse audits your page across four categories, each producing a score from 0–100.

Performance

Core Web Vitals (LCP, CLS, INP), Time to Interactive, Speed Index, and more — simulated on a mid-tier mobile device over a 4G connection.

Accessibility

Automated checks powered by axe-core, covering ARIA usage, color contrast, keyboard navigation, and semantic markup.

SEO

Crawlability, meta tags, structured data, mobile friendliness, and other ranking-relevant signals.

Best Practices

HTTPS enforcement, modern JavaScript APIs, secure headers, browser compatibility, and more.

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Three ways to run Lighthouse

Chrome DevTools

Open the Lighthouse panel in Chrome DevTools and click Generate report. No installation required.

CLI quickstart

Install the lighthouse package globally and audit any URL from your terminal. Best for automation and scripting.

Node.js quickstart

Import Lighthouse as a Node module and integrate audits directly into your scripts or tooling.

Lighthouse CI

Run Lighthouse on every commit, track score changes over time, and block regressions in CI.

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Requirements

Lighthouse requires Node.js 22 (LTS) or later. Check your version with: 
node --version

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Next steps

CLI quickstart

Install and run your first audit in under a minute

Node.js quickstart

Use Lighthouse programmatically in your Node.js scripts

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