Test and monitor Core Web Vitals across hundreds or thousands of pages. Compare Lighthouse lab results with real-user CrUX data, track changes over time, and catch performance regressions early.
No credit card required. Import URLs from a sitemap, CSV, or a pasted list.
Core Web Vitals monitoring is the continuous process of testing important pages, storing the results, and tracking how their performance changes over time. Unlike a one-time Core Web Vitals test, monitoring shows whether a page is improving, gradually becoming slower, or regressing after a release.
psiLynx runs scheduled Lighthouse audits across your URL list and displays available Chrome User Experience Report data alongside the lab results. This gives you two different views of performance: controlled Lighthouse measurements for consistent testing, and real-user CrUX field data for LCP, INP, and CLS where Google has enough traffic data.
Lighthouse audits run through the official Google PageSpeed Insights API. No local installation is required, and you can start with the free plan.
A Core Web Vitals test usually begins with a single URL. That is useful for diagnosing one page, but it does not show whether the same problem affects other templates, devices, or sections of the website. A fast homepage can easily hide slow product pages, unstable category layouts, or JavaScript-heavy checkout flows.
psiLynx lets you import a sitemap, CSV file, or custom URL list and run Lighthouse tests across the entire set. Every page is checked on mobile and desktop, making it easier to find patterns that a manual test would miss.
Add pages from a sitemap, upload a CSV, or paste a list of URLs. You can monitor a representative set of templates or test a much larger part of the website.
Test each URL under consistent Lighthouse conditions and compare how performance differs between mobile and desktop.
Sort and group results to see whether a problem is isolated to one URL or repeated across a product, category, article, or landing-page template.
Testing only the homepage gives you a narrow view of website performance. Product pages, category listings, articles, checkout steps, localized pages, and mobile templates can all produce different Core Web Vitals results.
To understand site-wide performance, you need to test every important page type and repeat those tests over time. That is how you find template-level problems instead of assuming that one healthy URL represents the entire website.
A single result tells you how a page performed during one test. Historical monitoring shows whether that result is normal, whether performance is gradually declining, and when a significant change first appeared.
Every scheduled run is stored. Instead of seeing only today's result, you can compare it with previous tests and follow the performance history of each URL.
psiLynx highlights pages and metrics that changed between runs, helping you narrow the problem down to the period when the regression first appeared.
Compare repeatable Lighthouse lab results with available real-user CrUX data. Lab data helps diagnose changes quickly, while field data shows how real Chrome users experienced the page over time.
Lighthouse and CrUX answer different questions. Lighthouse runs a controlled test under predefined conditions. It is useful for comparing pages, identifying technical problems, and detecting changes soon after they happen. Because the environment is controlled, you do not have to wait for weeks of user data before seeing a regression.
CrUX contains field data collected from eligible Chrome users. It reports real-user Core Web Vitals, including LCP, INP, and CLS, over a rolling period. However, field data is only available when a URL or origin has enough traffic to meet Google's reporting thresholds.
psiLynx shows these sources separately. Lighthouse results provide frequent and consistent testing across your URL list, while available CrUX data shows how real users experience the site.
| Lighthouse lab data | CrUX field data |
|---|---|
| Controlled test environment | Real Chrome user experiences |
| Available after each audit | Depends on traffic availability |
| Useful for fast regression detection | Used for Google's Core Web Vitals assessment |
| Includes diagnostic performance metrics | Includes field LCP, INP, and CLS |
| Can test every imported URL | May be unavailable for low-traffic URLs |
Google Core Web Vitals measure loading performance, responsiveness, and visual stability. psiLynx displays available CrUX field metrics alongside Lighthouse lab results and diagnostics.
LCP measures how long it takes for the largest visible content element to render. Slow LCP is often connected to server response time, large images, fonts, render-blocking resources, or delayed client-side rendering.
INP measures how quickly a page responds to user interactions such as clicks, taps, and keyboard input. It is a field metric based on real interactions and is available through CrUX when the page or origin has sufficient data. Lighthouse does not directly measure real-user INP during a standard audit.
CLS measures unexpected layout movement while a page is open. Common causes include images without dimensions, injected content, ads without reserved space, web fonts, and components that appear above existing content.
A Core Web Vitals report should show more than one score. psiLynx keeps page-level results, historical comparisons, mobile and desktop data, available CrUX metrics, and Lighthouse diagnostics in one place.
Teams can use these reports to identify affected templates, verify whether a fix improved performance, and share the results with developers, SEO specialists, clients, or other stakeholders.
Public report links and PDF export are available; the number of projects and scheduled runs depends on your plan.
A one-time Core Web Vitals test helps you understand how a page performs right now. Continuous monitoring repeats that test, keeps the history, and shows when results begin to change.
Core Web Vitals are part of Google's page experience systems, but they are not a replacement for relevance, content quality, or other ranking signals. Passing Core Web Vitals does not guarantee higher rankings, and a poor result does not automatically remove a page from search.
Their practical SEO value is broader than a single ranking factor. Slow loading, delayed interactions, and unstable layouts can affect user experience, conversion rates, engagement, and the overall quality of important landing pages. Monitoring helps SEO and development teams find performance regressions before they remain unnoticed for weeks.
How Core Web Vitals problems slowly damage SEO performance →
The questions teams ask before they start testing Core Web Vitals with psiLynx.
Import your URLs, run Lighthouse audits on mobile and desktop, track historical results, and view available CrUX field data in one place.