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Measure

See how well your website performs. Then, get tips to improve your user experience. Sign in to track your progress over time.

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Run tests on your site

Enter your site's URL to see how well it performs across all audits.

Look at what matters

See your site's performance across the areas you care about.

Get tips for improving

Each test comes with helpful steps to improve your site's results.
When you measure your site, web.dev uses Lighthouse, an open-source, automated tool for improving the quality of web pages. Lighthouse will audit your site in the following categories:
Performance
Audits for metrics like first paint and time to interactive to determine lag.
Best Practices
Looks for everything from HTTPS usage to correct image aspect ratios.
SEO
Checks for best practices to ensure your site is discoverable.
Accessibility
Checks for common issues that may prevent users from accessing your content.
All tests are run using a simulated mobile device, throttled to a fast 3G network & 4x CPU slowdown.