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Lighthouse analyzes web pages and apps, collecting modern performance metrics and surfacing actionable insights on developer best practices. Run it from Chrome DevTools, the command line, or as a Node module — and get scores across Performance, Accessibility, SEO, and Best Practices.

CLI Quickstart

Install Lighthouse and run your first audit in under a minute

Node.js Quickstart

Use Lighthouse programmatically in your Node.js scripts

Configuration

Customize audits, throttling, categories, and output formats

User Flows

Audit multi-step interactions with navigation, timespan, and snapshot modes

What Lighthouse measures

Performance

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

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

How to run Lighthouse

1

Choose your entry point

Lighthouse runs in three ways: directly inside Chrome DevTools (no install needed), via the Node CLI for automation, or as a Node module for programmatic integration.
2

Point it at a URL

Whether you use DevTools, the CLI (lighthouse https://example.com), or the Node API, Lighthouse launches Chrome, loads the page under controlled conditions, and collects data.
3

Read your report

Lighthouse generates an HTML report (or JSON/CSV) with scores, metric values, failing audits, and step-by-step guidance for every issue found.
4

Integrate and automate

Add Lighthouse to CI with Lighthouse CI, write custom audits for your own checks, or embed results in your toolchain.

Explore the docs

Running in DevTools

Zero-install auditing right in your browser

CLI reference

Every flag and option for the command-line tool

Node API reference

Full API surface for programmatic use

Throttling

How network and CPU throttling works

Plugins

Build and share custom audit categories

Understanding results

What the LHR object contains and how scores work

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