Google PageSpeed Insights

Visit Website

Introduction

PageSpeed Insights (PSI) is Google’s free web tool, at pagespeed.web.dev, that reports on the performance of a page on mobile and desktop and suggests improvements. Google’s documentation explains that PSI provides both lab and field data: lab data is generated by Lighthouse, and real-user field data comes from the Chrome User Experience Report (CrUX).

The field data section shows how real Chrome users experienced the page and origin over the previous 28-day collection period, for Core Web Vitals and related metrics: First Contentful Paint, Largest Contentful Paint, Interaction to Next Paint and Cumulative Layout Shift. Google’s documentation notes that PSI’s field data is updated daily, whereas the CrUX dataset on BigQuery is monthly and origin-level.

Below the field data, the Lighthouse lab report lists performance, accessibility, best practices and SEO scores with diagnostics and opportunities. PSI is also available as an API (PageSpeed Insights API v5), which many monitoring tools and scripts use.

How it compares: Lighthouse alone gives lab data without the CrUX field view; WebPageTest and GTmetrix give deeper waterfalls and location choice; DebugBear, SpeedCurve and similar tools add scheduled monitoring and RUM. PSI is the fastest way to see whether real users are passing Core Web Vitals.

In the quality loop PSI belongs to the performance stage, and it is often the first check before and after a release.

Features

1. Field data from CrUX: Real-user Core Web Vitals over a 28-day window, at page and origin level.
2. Lighthouse lab data: Performance, accessibility, best practices and SEO audits.
3. Mobile and desktop views: Separate reports for each form factor.
4. Opportunities and diagnostics: Actionable suggestions with estimated savings.
5. PSI API: Programmatic access for monitoring and scripts.

Pros

1. Free: No account required.
2. Real-user data: Shows whether actual visitors pass Core Web Vitals.
3. Authoritative: Uses the same CrUX data Google publishes.

Cons

1. Field data needs traffic: Low-traffic pages may have no CrUX data.
2. No scheduling: Single tests only, unless you build on the API.
3. Lab variance: The Lighthouse section varies between runs.

Usage and Links (Example)

Visit pagespeed.web.dev, enter a URL, and review the field data first (are real users passing?), then the lab diagnostics for causes. For automation, call the API:

curl "https://www.googleapis.com/pagespeedonline/v5/runPagespeed?url=https://example.com&strategy=mobile"

Use an API key for regular use and store results to track trends.

Useful links:

• About PageSpeed Insights

Pricing

Free. The API is free to use within Google’s quotas; see the documentation.

Recommended for?

• Anyone checking Core Web Vitals for a page or site
• SEO teams monitoring real-user performance
• Developers who want a quick lab and field snapshot

Conclusion

PageSpeed Insights is the quickest free way to see both real-user Core Web Vitals and Lighthouse diagnostics for a page. Pair it with a monitoring tool or Lighthouse CI if you need trends and alerts.