Lighthouse

Lighthouse is a free, open-source tool for auditing web pages across performance, accessibility, SEO, and best practices. It is best suited to web developers who want actionable findings and a way to check for regressions in continuous integration. Its range of run options is useful, but browser and authentication requirements can narrow which workflow fits.

Overview

Enter a URL and Lighthouse runs audits, then produces a report with results and explanations of why checks matter and how to address failures. That context helps developers turn findings into improvement work rather than treating an audit score as an endpoint.

It can audit public pages and pages requiring authentication, but workflow choice matters: DevTools can handle authenticated and local pages, while the Chrome extension cannot. The extension is therefore a poor fit when those targets matter.

Key features

Audits and reports

Lighthouse covers performance, accessibility, SEO, and best practices. Its performance audits use modern metrics and include insights. Reports can be exported as JSON or HTML, with CSV also supported by the command-line interface. That mix suits both developers reviewing results directly and teams that need report data in another process.

Ways to run and customize

Run it in Chrome DevTools, from the command line, as a Node module, or through a web UI without installation. Stack packs add platform-specific recommendations, while plugins let domain experts contribute audits and report categories. Those options make the tool adaptable, though the command-line and Node workflows require Node 22 (LTS) or later and Google Chrome installed.

Sharing and continuous integration

Reports can be viewed online and shared through Lighthouse Viewer using report JSON; the documentation also describes sharing them as secret GitHub Gists. Lighthouse integrates with continuous integration systems, and Lighthouse CI can help prevent regressions. WebPageTest can produce Lighthouse reports alongside its analysis, while HTTPArchive stores Lighthouse results in BigQuery.

Privacy and contribution

The first CLI run asks whether Lighthouse 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: its open-source plan costs nothing and includes on-page audits and API access. There is no free trial because there is no paid plan to trial. Its zero price comes with no stated usage cap, though teams must account for the Node and Chrome requirements when choosing command-line or Node workflows.

Platforms

Lighthouse is listed for API, extension, Linux, macOS, web, and Windows. The web UI runs without installation. For CLI and Node use, the machine needs Google Chrome as well as Node 22 (LTS) or later. DevTools is the better choice for local or authenticated pages; the extension cannot audit either.

Who it's for

Lighthouse is aimed at web developers who need guidance that is relevant and actionable. It works well for developers auditing a page, teams incorporating checks into CI, and domain specialists extending audit coverage through plugins. It is less suitable when a user needs the Chrome extension to inspect local or authenticated pages, or cannot meet the runtime requirements for CLI or Node workflows.

Pros and cons

Pros

• Useful explanations: reports explain why an audit matters and how to address failures, so findings can guide fixes.
• Flexible workflows: DevTools, CLI, Node, and a no-install web UI accommodate different ways of working.
• CI and extensibility: Lighthouse CI can help catch regressions, while stack packs and plugins tailor recommendations and audits.
• No purchase barrier: the open-source tool is free, with on-page audits and API access.

Cons

• Extension restrictions: it cannot test local sites or authenticated pages, limiting its usefulness for those targets.
• CLI and Node prerequisites: both workflows require Node 22 (LTS) or later and Google Chrome.
• Run choice affects coverage: DevTools handles authenticated pages where the extension does not, so users must select the right workflow.

Alternatives

For a dedicated SEO crawler rather than Lighthouse's broader page-quality audits, consider Checkbot: its free Basic plan allows 100 URLs per crawl, unlimited crawls and sites, and is ad supported; the yearly Professional plan is $10 a year, billed $120 p.

Open SEO Crawler is a free, MIT-licensed, self-hosted option with unlimited URLs and no account, API key, or per-URL billing, making it a fit when those properties matter.

Screaming Frog SEO Spider offers a free crawl capped at 500 URLs and a paid licence with unlimited URLs, so it suits users who need a crawler and may outgrow that cap.

WebSite Auditor has a free plan capped at 500 URLs and one project, with no paid report exports; its Professional plan costs $149 a year. It is an option when a project-based SEO auditing workflow is preferable.

A1 Website Analyzer offers a free mode that continues after a 30-day evaluation period, with 500 page URLs per website and 500 imported URLs; consider it when those limits fit your needs.

Beam Us Up is a free SEO crawler with no limits stated.

Crab is an open-source option with no URL limits and no subscriptions.

FreeCrawl is a free, self-hosted option with unlimited URLs and no paid tier.

Browse SEO Audit Software for more options.

Verdict

Choose Lighthouse if you are a web developer who wants free, adaptable audits with explanations and a path into CI. Its central advantage is combining several page-quality audit categories with actionable reports; its chief drawback is that the extension cannot cover local or authenticated targets, while CLI and Node workflows bring runtime and browser prerequisites. Look elsewhere if you need a dedicated crawler or a workflow that avoids those constraints.