PageSpeed Insights
A Google tool combining Lighthouse lab data with CrUX field data for any public URL. Shows both diagnostic scores and real-user metrics.
Definition
PSI at pagespeed.web.dev provides a dual view: lab data from Lighthouse (performance score, diagnostics) and field data from CrUX (real-user LCP, INP, CLS, FCP, TTFB). It is the official tool Google recommends for evaluating CWV pass/fail.
Dual-Data Approach
Lab Data: Lighthouse scores from a simulated run. Field Data: CrUX data from real Chrome users over 28 days. If a URL has under ~1,000 visits, field data is empty.
Common Misunderstandings
Many developers look only at the Lighthouse score and ignore field data. Field data is the authoritative source for CWV pass/fail. PSI showing Good field LCP but Poor lab LCP is common and means real users have faster connections than the Lighthouse simulation.
Origin vs URL
PSI shows data at origin (entire domain) or URL level. Origin aggregates all pages. URL reports are more actionable.
Note
Common questions
- Q. Why no field data?
- A. URL needs at least ~1,000 visits in CrUX dataset.
- Q. Can I use PSI for auth pages?
- A. No. Only publicly accessible URLs. Use RUM or Lighthouse CLI.
Key takeaways
- Combines Lighthouse (lab) and CrUX (field).
- Field data is authoritative for CWV.
- Needs ~1,000 visits for field data.
- 28-day rolling window.
At a glance
- Type
- Public tool
- Data
- Lab + Field
- API
- Yes
Sources
How Atomic Glue helps
Atomic Glue uses PSI programmatically to batch-audit and compare competitors. SEO/GEO services.
Get in touchUnderlined terms have their own entry. Selecting one shows it on the map below.
Atomic Glue. "PageSpeed Insights." Glossary.atomicglue.co/glossary/pagespeed-insights
How PageSpeed Insights connects
A Google tool combining Lighthouse lab data with CrUX field data for any public URL. Shows both diagnostic scores and real-user metrics.
Definition
PSI at pagespeed.web.dev provides a dual view: lab data from Lighthouse (performance score, diagnostics) and field data from CrUX (real-user LCP, INP, CLS, FCP, TTFB). It is the official tool Google recommends for evaluating CWV pass/fail.
Dual-Data Approach
Lab Data: Lighthouse scores from a simulated run. Field Data: CrUX data from real Chrome users over 28 days. If a URL has under ~1,000 visits, field data is empty.
Common Misunderstandings
Many developers look only at the Lighthouse score and ignore field data. Field data is the authoritative source for CWV pass/fail. PSI showing Good field LCP but Poor lab LCP is common and means real users have faster connections than the Lighthouse simulation.
Origin vs URL
PSI shows data at origin (entire domain) or URL level. Origin aggregates all pages. URL reports are more actionable.
Note
Public data. Anyone can look up any URL. 28-day rolling window for field data. Recent optimizations may not appear immediately.
Common questions
Q: Why no field data?
A: URL needs at least ~1,000 visits in CrUX dataset.
Q: Can I use PSI for auth pages?
A: No. Only publicly accessible URLs. Use RUM or Lighthouse CLI.
Key takeaways:
Combines Lighthouse (lab) and CrUX (field).
Field data is authoritative for CWV.
Needs ~1,000 visits for field data.
28-day rolling window.