LCP, INP, and CLS — measured on every page.

Core Web Vitals

Core Web Vitals are Google's user experience metrics that directly impact search rankings. Largest Contentful Paint (LCP) measures loading speed, Interaction to Next Paint (INP) measures responsiveness, and Cumulative Layout Shift (CLS) measures visual stability. Since 2021, these metrics are a confirmed ranking signal. Pages that fail any threshold get deprioritized in search results — and users bounce faster from slow, janky sites.

How It Works

EchoBat's Render engine runs Lighthouse audits via headless Chrome on sampled pages during the crawl. CrUX field data (p75 values) is fetched when available and takes priority over lab measurements. The Core Web Vitals lens then classifies each page against Google's official thresholds and ranks pages by severity — pages in the "Poor" range surface first.

Proof Returned in the Report

Every Core Web Vitals finding is tied to crawl evidence: affected URLs, the source signal, severity, score impact, and the next action exposed in the portal, CLI JSON, and MCP tools.

Sample Evidence Fields

  • LCP (Largest Contentful Paint): Target under 2.5 seconds. Identifies slow-loading hero images, fonts, and above-the-fold content.
  • INP (Interaction to Next Paint): Target under 200ms. Detects sluggish JavaScript event handlers and long tasks blocking the main thread.
  • CLS (Cumulative Layout Shift): Target under 0.1. Finds images without dimensions, dynamically injected content, and late-loading ads.

Why It Matters

  • Identify pages failing Google's CWV thresholds before they tank your rankings
  • Field data (real users) and lab data (controlled tests) in one view
  • Per-page breakdown — not just site-wide averages
  • Clear good/needs-improvement/poor classification for each metric

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