Introduction to Lighthouse  |  Chrome for Developers
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Ensure CSP is effective against XSS attacks
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Introduction to Lighthouse
Stay organized with collections
Save and categorize content based on your preferences.
Lighthouse is an open-source,
automated tool to help you improve the quality of web pages. You can run it on
any web page, public or requiring authentication. It has audits for performance,
accessibility, SEO, and more.
You can run Lighthouse in Chrome DevTools, from the command line, or as a Node
module. Give Lighthouse a URL to audit, it runs a series of audits against the page,
and then it generates a report on how well the page performed. Use the failed
audits as indicators for how to improve the page. Each audit has a reference
that explains why the audit is important, as well as how to fix it.
You can also use
Lighthouse CI
to prevent regressions on your sites.
Get started
Choose the Lighthouse workflow that suits you best:
In Chrome DevTools. Audit pages that require authentication and
read your reports in a user-friendly format, right from the browser.
From the command line. Automate your Lighthouse runs with shell
scripts.
As a Node module. Integrate Lighthouse into your continuous
integration systems.
From a web UI. Run Lighthouse and link to reports, no installation
needed.
Note: The CLI and Node workflows require you to have an instance of Google
Chrome installed on your machine.
Run Lighthouse in Chrome DevTools
Lighthouse has its own panel in Chrome DevTools. To run a report:
Download Google Chrome for Desktop.
Open Chrome, and go to the URL you want to audit. You can audit any URL on
the web.
Open Chrome DevTools.
Click the Lighthouse tab.
To the left is the viewport of the web page to be audited. The right
is the Chrome DevTools Lighthouse panel.
Click Analyze page load. DevTools shows you a list of audit categories.
Leave them all enabled.
Click Run audit. After 30 to 60 seconds, Lighthouse gives you a report on
the page.
A Lighthouse report in Chrome DevTools.
Install and run the Node command line tool
To install the Node module:
Download Google Chrome for Desktop.
Install the current Long-Term Support
version of Node.
Install Lighthouse. The -g flag installs it as a global module.
npm install -g lighthouse
To run an audit:
lighthouse <url>
To see all the options:
lighthouse --help
Run the Node module programmatically
See Using programmatically
for an example of running Lighthouse programmatically, as a Node module.
Run PageSpeed Insights
To run Lighthouse on PageSpeed Insights:
Go to PageSpeed Insights.
Enter a web page URL.
Click Analyze.
The PageSpeed Insights website.
Run Lighthouse as a Chrome Extension
Caution: Unless you have a specific reason, you should use
Chrome DevTools rather than this Chrome Extension workflow. The
DevTools workflow allows for testing local sites and authenticated pages, while
the extension does not.
To install the extension:
Download Google Chrome for Desktop.
Install the Lighthouse Chrome Extension from the Chrome Webstore.
To run an audit:
In Chrome, go to the page you want to audit.
Click
Lighthouse, next to the Chrome address bar or in Chrome's extension menu.
Once clicked, the Lighthouse menu expands.
The extension prompts you to generate a report.
Click Generate report. Lighthouse runs its audits against the
currently-focused page, then opens up a new tab with a report of the results.
A Lighthouse report generated from the extension.
Share and view reports online
Use the Lighthouse Viewer
to view and share reports online.
The Lighthouse Viewer
Share reports as JSON
The Lighthouse Viewer needs the JSON output of a Lighthouse report. Generate
the JSON outputs as follows:
From a Lighthouse report. Click more_vert
for the menu, then click  Save as JSON
Command line. Run:
shell
lighthouse --output json --output-path <path/for/output.json>
To view the report data:
Open the Lighthouse Viewer.
Drag the JSON file onto the Viewer, or click anywhere in the Viewer to open
your file navigator and select the file.
Share reports as GitHub Gists
If you don't want to manually pass around JSON files, you can also share your
reports as secret GitHub gists. One benefit of gists is free version control.
To export a report as a gist from the report:
Click the more_vert menu, then click
Open In Viewer. The report is located at
https://googlechrome.github.io/lighthouse/viewer/.
From the Viewer, click more_vert menu,
then click
Save as Gist. The first time you do this, a popup asks permission to
access your basic GitHub data, and to read and write to your gists.
To export a report as a gist from the CLI version of Lighthouse,
manually create a gist and copy-paste the report's
JSON output into the gist. The gist filename containing the JSON output must
end in .lighthouse.report.json. See Share reports as JSON for an
example of how to generate JSON output from the command line tool.
To view a report that's been saved as a gist:
Add ?gist=<ID> to the Viewer's URL, where <ID> is the ID of the gist.
text
https://googlechrome.github.io/lighthouse/viewer/?gist=<ID>
Open the Viewer, and
paste the URL of a gist into it.
Lighthouse extensibility
Lighthouse aims to provide guidance that is relevant and actionable for all web
developers. To this end, there are two features available that allow you to
tailor Lighthouse to your specific needs.
Stack packs
Developers use many different technologies (backend, content management systems,
and JavaScript frameworks) to build their web pages. Instead of surfacing
general recommendations, Lighthouse provides relevant and actionable advice,
depending on the tools used.
Stack packs allow Lighthouse to detect what platform your site is built on
and display specific stack-based recommendations. These recommendations are
defined and curated by experts from the community.
To contribute a stack pack, review the
Contributing Guidelines.
Lighthouse plugins
Lighthouse plugins allow domain experts to extend the functionality of
Lighthouse for their community's specific needs. You can leverage
the data that Lighthouse collects to create new audits. At its core, a
Lighthouse plugin is a node module that implements a set of checks to be run by
Lighthouse and added to the report as a new category.
For more information about how to create your own plugin, check out our
Plugin Handbook
in the Lighthouse GitHub repo.
Integrate Lighthouse
If you're a company or an individual who is integrating Lighthouse as part of
the products or services you're offering, that's great! We want as many people
as possible to use Lighthouse.
Refer to the
Guidelines and Brand Assets for Integrating Lighthouse
to show that Lighthouse is used, while protecting our brand.
Contribute to Lighthouse
Lighthouse is open source and
contributions are welcome!
Check out the repository's
Issue tracker to find
bugs that you can fix,
or audits that you can create or improve upon. The Issues are a good place to
discuss performance metrics, ideas for new audits, or anything else related to
Lighthouse.
Except as otherwise noted, the content of this page is licensed under the Creative Commons Attribution 4.0 License, and code samples are licensed under the Apache 2.0 License. For details, see the Google Developers Site Policies. Java is a registered trademark of Oracle and/or its affiliates.
Last updated 2025-06-02 UTC.
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