Lighthouse

Lighthouse is a free, open-source tool that audits web pages for quality areas including performance, accessibility, best practices and SEO. Enter a URL to generate a report containing audit results and references that explain their significance and how to address failures. It is intended to give web developers relevant, actionable guidance.

Lighthouse can run in Chrome DevTools, from the command line, as a Node module or through a web interface without installation. DevTools can audit authenticated pages and local sites; the Chrome extension workflow cannot audit authenticated pages or local sites. Reports are available in JSON or HTML, and the CLI also supports CSV output. Stack packs add platform-specific recommendations, while plugins can add audits and report categories. Lighthouse can be integrated into continuous integration, and Lighthouse CI can help prevent regressions. Reports can be viewed and shared online using report JSON. The CLI and Node workflows require Node 22 LTS or later and Google Chrome installed. On first CLI use, Lighthouse asks whether it may anonymously report runtime exceptions; opting out does not affect use.

Lighthouse offers several ways to audit web pages and inspect reported results. Note the browser and runtime requirements for command-line and Node use, and the extension’s limits on authenticated and local pages.

Lighthouse suits web developers who want to audit performance, accessibility, SEO and other page-quality areas. Its multiple run options also suit developers working with command-line tools or continuous integration.

Lighthouse is a free, open-source auditing tool for web developers who need to assess page quality and act on the results. Its combination of detailed reports and CI support makes it a strong fit for ongoing improvement; the best workflow depends on whether you need to audit authenticated or local pages.

Overview

Give Lighthouse a URL and it audits the page, returning results with references that explain the purpose of each check and how to address failures. That guidance helps developers turn findings into concrete fixes instead of stopping at a score. It covers performance, accessibility, SEO, and best practices, making it useful for broad page-quality reviews as well as focused checks.

Lighthouse is designed to provide relevant, actionable guidance to web developers. It can audit both public pages and pages behind authentication, but the available targets vary by workflow: Chrome DevTools can handle authenticated and local pages, while the Chrome extension cannot handle either. Choosing the extension for those pages will leave the audit incomplete.

Key features

Audits and reports

Performance audits use modern metrics and include insights. Reports can be produced as JSON or HTML, and the CLI also supports CSV. Those formats make it possible to review results directly or use them in other processes. Reports can also be viewed online with Lighthouse Viewer and shared using report JSON.

Flexible workflows and extension points

Run Lighthouse in Chrome DevTools, from the command line, as a Node module, or through a web UI without installing it. The command-line and Node workflows require Google Chrome installed, and the repository specifies Node 22 LTS or later. That requirement matters for teams adding Lighthouse to existing development or CI environments.

Stack packs add recommendations for particular platforms, and plugins let domain experts contribute audits and report categories. Lighthouse can be integrated into continuous integration systems; Lighthouse CI can help teams catch site regressions. WebPageTest can produce Lighthouse reports alongside its own analysis, while HTTPArchive stores Lighthouse results in BigQuery.

On the first CLI run, Lighthouse asks whether it may anonymously report runtime exceptions. Opting out does not affect use. The project is open source and welcomes contributions through its repository.

Pricing

Lighthouse is free and open source. The free plan costs nothing and includes on-page audits and API access. There is no free trial; the free plan itself is the ongoing offering. No paid Lighthouse plan is provided, so developers can use its audit and reporting workflows without a subscription.

Platforms

Lighthouse is available as an API, browser extension, web interface, and for Linux, macOS, and Windows. Its run options span Chrome DevTools, CLI, Node module, and web UI. The CLI and Node options require Google Chrome, and the Node runtime must be version 22 LTS or later. The extension has narrower page access than DevTools: it cannot audit authenticated or local pages.

Who it's for

Lighthouse suits web developers and teams that want actionable audits across performance, accessibility, SEO, and best practices, especially when they need to track quality through CI. Its reports and customization options also suit teams that want to adapt findings to a platform or domain. It is less suitable for someone who needs an extension-only workflow to inspect a local or authenticated page, or who wants a crawler focused on managing a large number of URLs.

Pros and cons

• Pros: Free, open-source access includes on-page audits and API access, with no paid tier required.
• Pros: Multiple run options and JSON, HTML, and CLI CSV reports support both direct review and automated workflows.
• Pros: DevTools can audit authenticated and local pages, and CI integration can help detect regressions.
• Cons: The Chrome extension cannot audit authenticated or local pages, limiting its usefulness for private and in-development targets.
• Cons: CLI and Node use depend on Chrome being installed and Node 22 LTS or later being available.

Alternatives

For broader site crawling and URL quotas, Website Crawler offers a free plan with 10 pages per day and one project, plus a Starter plan at $10 a month with 2,000 pages per month and three projects. It is the better fit when page-volume limits and project counts are central to the decision; Lighthouse is aimed at audits and developer guidance.

A1 Website Analyzer is a freemium option for macOS and Windows with a free mode that continues after a 30-day evaluation period. Consider it when a desktop website analyzer is a better match for your workflow.

Checkbot has a free, ad-supported plan with 100 URLs per crawl and unlimited crawls and sites. It is worth considering when you need repeated crawls with a fixed per-crawl URL allowance.

CrawlCenter is a web-based crawler whose Basic plan includes one project, 50 URLs per project, and unlimited crawler runs, with custom pricing for that plan. Its Silver plan costs $3 a month. Choose it when managing crawler projects and repeated runs is the main need.

CrawlRaven has a free plan for one website with Google Search Console insights and keyword and page performance. It is a relevant option when those search-performance insights are the priority.

Geolify offers a free plan with one brand, three audits per month, five weekly prompt monitors, and 30-day audit history. Its Starter plan costs $23 a month. Consider it when brand audits and prompt monitoring match your needs.

Netpeak Spider provides a free desktop plan for macOS and Windows, capped at 500 URLs, five threads, and two devices per user. It may suit a desktop crawling workflow with those limits.

Screaming Frog SEO Spider has a free plan capped at 500 URLs per crawl and a paid licence with unlimited URLs. Consider it when crawl size is the deciding factor.

Browse SEO Audit Software for more options in the category.

Verdict

Lighthouse is the right choice for web developers who want free, extensible audits with actionable reports and a path to CI regression checks. Its strongest reason to choose it is the breadth of audit and workflow options without a subscription. Look elsewhere if you need a dedicated crawler with URL quotas and project management, or if your only workable interface is the extension for authenticated or local pages.