CWV Speed Studio Core Web Vitals
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Engine Active
98
Speed Score
✓ Good Rating
LCP
1.2 s
Target < 2.5s
CLS
0.012
Target < 0.10
INP
65 ms
Target < 200ms
FCP
0.8 s
Target < 1.8s
TTFB
180 ms
Target < 800ms

⚡ Core Web Vitals Auditor

Analyze live URLs or raw HTML markup for LCP, CLS, INP, FCP, and TTFB bottlenecks.

Diagnostic Findings & Recommendations

🛠️ HTML Speed Transformer

Automated AST speed rewrites: inject missing dimensions, lazy loading, font preconnects, and script deferral.

Transformation Options

Fix Missing Image Dimensions

Adds width/height and aspect-ratio to prevent layout shifts (CLS)

Native Lazy Loading & Async Decoding

Adds loading="lazy" & decoding="async" to offscreen images

Font Preconnect & Display Swap

Eliminates Flash of Invisible Text (FOIT) with &display=swap

Defer Render-Blocking Scripts

Adds defer to scripts in head to unblock main thread interactivity

Preload Hero Image (fetchpriority="high")

Prioritizes LCP hero image fetch in browser preload scanner

Optimization Summary

  • Ready to optimize. Click "Transform HTML Now".

📱 PWA & Service Worker Studio

Generate production Web App Manifest, Service Worker caching strategies, and offline fallback.

🖼️ OpenGraph & Social Previewer

Real-time mockups for Google Search SERP, Twitter Cards, and LinkedIn snippets.

Google Search Preview

G example.com > speed-studio
CWV Speed Studio | Core Web Vitals Optimization Engine
High-performance Core Web Vitals optimization engine, instant HTML speed transformer, PWA generator...

Twitter / X Card Preview

⚖️ Performance Diff Comparator

Measure before vs after speed gains, metric deltas, and resolved audit findings.

Comparative Delta Analysis

+38 pts
Score improved from 58 to 96 with 4 diagnostic issues resolved.

🚀 Cache-Control & Headers Exporter

Generate production caching rules for Netlify, Vercel, Nginx, Cloudflare, Apache, and Next.js.

_headers Production Speed Rules 
Loading configuration...

🤖 AI Agent & MCP Hub

Integrate CWV Speed Studio directly into Claude Desktop, Cursor, Cline, and Zed via Model Context Protocol.

claude_desktop_config.json MCP Stdio Transport 
Loading MCP configuration...

Exposed Agent Tools (6 Tools)

Tool
audit_url(url, device)
Audits live URL for LCP, CLS, INP, FCP, TTFB and returns full score report.
Tool
transform_html(html, options)
Automated HTML AST optimization: fixes layout shift dimensions, lazy loading, font preconnects.
Tool
generate_pwa(name, theme_color, strategy)
Generates W3C web manifest, service worker caching engine, and offline page.
Tool
generate_cache_headers(platform)
Outputs immutable caching and security header configs for Netlify, Vercel, or Nginx.

📖 Core Web Vitals Best Practices & CLI Cheatsheet

Google 2024-2026 Core Web Vitals Official Thresholds and Commands.

CWV Metric Thresholds (Google 2024+)

Metric Good (Pass) Needs Work Poor
LCP (Largest Contentful Paint) ≤ 2.5s 2.5s - 4.0s > 4.0s
CLS (Cumulative Layout Shift) ≤ 0.10 0.10 - 0.25 > 0.25
INP (Interaction to Next Paint) ≤ 200ms 200ms - 500ms > 500ms
FCP (First Contentful Paint) ≤ 1.8s 1.8s - 3.0s > 3.0s
TTFB (Time to First Byte) ≤ 800ms 800ms - 1800ms > 1800ms

CLI Commands Quick Reference

Terminal Commands cwv-speed 
# 1. Audit a live URL
cwv-speed audit https://example.com --device mobile

# 2. Optimize an HTML file
cwv-speed optimize input.html -o output.html --hero-preload

# 3. Launch CWV Speed Studio (Web UI)
cwv-speed ui --port 8448 --open

# 4. Run CI/CD Performance Gate
cwv-speed ci-gate https://staging.example.com --min-score 90 --max-cls 0.05

# 5. Start MCP Server for Claude / Cursor
cwv-speed mcp
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