Google Search Console is the primary source for Core Web Vitals data because it shows real user metrics (field data) from Chrome users who visit your site. Navigate to Experience > Core Web Vitals to see which URLs pass or fail for mobile and desktop. This is the dataset Google actually uses for ranking, so it's your source of truth. Reports update roughly every 28 days based on the previous 28-day window. PageSpeed Insights combines field data from the Chrome User Experience Report with lab data from Lighthouse. Enter any URL and you'll get specific LCP, INP, and CLS scores plus actionable recommendations. The lab data is synthetic (simulated on Google's servers), useful for diagnosing issues on new pages or low-traffic URLs that lack field data. We use PSI daily when auditing client sites because it breaks down exactly which resources are blocking renders or causing layout shifts. Chrome DevTools gives you live performance profiling. Open DevTools, go to the Performance or Lighthouse tab, and run an audit. This is critical for debugging because you can throttle network speed, simulate mobile devices, and see frame-by-frame what's causing a poor INP or CLS score. The Performance Insights panel in newer Chrome versions highlights Core Web Vitals issues directly in the timeline. Other tools worth mentioning: - Chrome UX Report dashboard (real user data by origin, updated monthly) - Web Vitals Chrome extension (shows metrics as you browse) - Crux API or BigQuery for bulk analysis across hundreds of URLs - Third-party monitoring like Calibre, SpeedCurve, or Cloudflare's RUM if you need historical trending At Ottawa SEO, we rely on Search Console for the pass/fail verdict and PageSpeed Insights for diagnostics. We only escalate to DevTools or paid monitoring when a site has persistent issues that aren't obvious from PSI's waterfall. For most clients, fixing the top three suggestions in PageSpeed Insights gets you from failing to passing within one reporting cycle.