Core Web Vitals
SEO-angle on Core Web Vitals — LCP, CLS, INP are ranking signals on mobile.
What this check measures
We fetch real-user Core Web Vitals field data from CrUX (Chrome User Experience Report) for your domain and compare against the thresholds: LCP < 2.5s, CLS < 0.1, INP < 200ms.
Why it matters
Core Web Vitals are a direct Google ranking signal (Page Experience). Failing sites get demoted on mobile results — modestly in isolation, significantly when combined with other weak signals.
How our audit detects it
Query CrUX API for p75 values of LCP, CLS, INP over the last 28 days. Fall back to PageSpeed Insights lab data if field data is unavailable.
Typical findings
- error_outlineLCP over 4s on mobile — usually unoptimized hero image.
- error_outlineCLS above 0.25 — images without width/height cause page-jump.
- error_outlineINP above 500ms — heavy JS blocks interaction.
How to fix
Preload LCP image with proper format (WebP/AVIF), set width/height on all images/videos/iframes, split long JS tasks, defer non-critical scripts. See /prompts/fix-core-web-vitals for step-by-step.
Copy-paste fix prompt for your stack
Lovable · Cursor · Bolt · v0 · Replit · Windsurf · Claude Code · Base44
Frequently asked questions
How much does failing CWV hurt rankings?expand_more
Want this checked on your site?
Pantra runs the full audit (SEO, Security, GEO, Performance, Schema, Technical, Images) in 10 seconds and generates stack-specific fix prompts.
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