Frequently Asked Questions

PageSpeed Insights is a free tool that analyzes your website's performance using Google's official API. It measures key metrics like loading speed, interactivity, and visual stability – the same factors that affect your Google search rankings.

Yes, completely free! We use Google's public PageSpeed Insights API to analyze your site. There are no hidden costs or premium features locked behind paywalls.

Very accurate – we use Google's official API, so you get the same data Google uses. That said, results can vary slightly between tests due to network conditions. For the best picture, run a few tests and look at the trends.

Mobile tests simulate a mid-range phone on a slower connection, while desktop tests use a faster setup. Most sites score lower on mobile because phones have less processing power and mobile networks can be slower.

Core Web Vitals are Google's three key metrics for measuring user experience: LCP (loading speed), INP (interactivity), and CLS (visual stability). Good scores in these metrics can help your search rankings.

The most common fixes include: optimizing images, enabling caching (try fast.site!), reducing JavaScript, and using a CDN. Check the Opportunities section in your report for specific recommendations.

Field Data comes from real Chrome users visiting your site – it's the most accurate reflection of actual performance. Lab Data is from controlled tests, which is great for debugging but may not match real-world conditions.

Google needs enough traffic to your site to generate Field Data. Newer or lower-traffic sites may not have enough data yet. Lab Data is always available though!

We recommend testing after any significant changes to your site. For ongoing monitoring, weekly or monthly tests help you spot trends and catch issues early.

fast.site uses edge caching to serve your content from locations closer to your visitors. This dramatically reduces server response times (TTFB) and can significantly improve your LCP score.