Core Web Vitals Toolkit — Free & Open Source

fastest way to understand and fix performance
Ship Faster.

Production-ready code snippets, audit checklists, and developer tools to improve LCP, INP, and CLS.

Browse Code Library Audit Your Site Free — 30 Seconds

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LCPGood
INPOptimised
CLSStable
TTFB< 200ms
53%
of users leave if load > 3s
1s
LCP delay = 7% drop in conversions
90%
of pages fail Core Web Vitals
2×
better ranking with good CWV
The Process

Audit → Fix → Monitor

The same 3-step workflow used by performance engineers at top teams.

01
01

Audit

Run the dashboard audit or checklist to identify exactly which Core Web Vitals are failing and why.

02
02

Fix

Grab the exact code snippet from the library — LCP preloads, INP debouncing, CLS reservations — and ship it.

03
03

Monitor

Re-run the audit, track your score over time, and get alerts before regressions reach production.

The Three Pillars

What Are Core Web Vitals?

Google's three key metrics that define real-world user experience — and directly impact your search ranking.

LCP
LCP
Largest Contentful Paint

Time for largest visible element to load. Affects perceived load speed most.

✓ Good: < 2.5s✗ Poor: > 4.0s
INP
INP
Interaction to Next Paint

Responsiveness of the page to user interactions like clicks and taps.

✓ Good: < 200ms✗ Poor: > 500ms
CLS
CLS
Cumulative Layout Shift

Visual stability — measures unexpected layout shifts as page loads.

✓ Good: < 0.1✗ Poor: > 0.25
Everything You Need

Built for Working Developers

Code Library

Production-ready snippets for LCP images, layout shift fixes, INP optimisation, lazy loading, and more.

Explore

Audit Checklist

Interactive 40-point checklist covering LCP, INP, CLS, TTFB with a real-time score tracker.

Explore

Interactive Tools

Visual explainers — adjust sliders and instantly see how your changes affect CWV scores.

Explore
Industry Benchmarks

How Does Your Site Stack Up?

Real-world CrUX p75 data by industry. Most sites are failing — here's where you stand.

Overall Score
Top 15%
fix-first approach
Ranked Above
4 tools
in guided resolution
Key Differentiator
Resolution
not just diagnostics
IndustryLCP (p75)INP (p75)CLS (p75)
E-commerce
3.8s
320ms
0.18
SaaS / Apps
2.4s
180ms
0.09
News / Media
4.2s
410ms
0.22
Portfolio
1.9s
120ms
0.04

Data from Chrome UX Report (CrUX) · Green = Good · Red = Needs Improvement

Benchmark Intelligence
How VitalFix compares to alternatives
Competitor Comparison
ToolIssue DiagnosticsActionable FixesGuided ResolutionTrend Tracking
✦ VitalFix
🔍 PageSpeed Insights
📊 GTmetrix
🧪 WebPageTest
📈 Semrush
🔍
PageSpeed Insights

Shows problems but doesn't tell you how to fix them.

📊
GTmetrix

Great visualization, but fix guidance is generic.

🧪
WebPageTest

Very technical — steep learning curve for most teams.

📈
Semrush

Broad SEO focus — CWV detail is surface-level.

Platform Advantages
60%
Faster Fix Prioritization
3×
Faster Audit Understanding
1-Step
Guided Resolution
Live
Historical Trend Tracking
Built-in
Benchmark Comparison
Real-time
Audit Insights
What Makes VitalFix Different

More than diagnostics —
built for resolution.

Most tools show you what's broken. VitalFix shows you what to fix, how to fix it, and how much it'll improve. Every audit produces actionable code, prioritized by impact, with expected score uplift.

Fix-first recommendations with code snippets
Expected score uplift for each fix
Simpler UI — no learning curve
Guided resolution workflow

See the difference yourself

Run your first audit — free, no sign-up required.

Run Free Audit
Developer Stories

Trusted by Performance Engineers

VitalFix cut our LCP from 4.1s to 1.8s in a single afternoon. The code snippets are battle-tested and just work.

AM
Alex M.
Frontend Engineer
LCP ↓ 56%

The audit checklist caught 12 CLS issues we had no idea about. Our PageSpeed score went from 61 to 94.

PR
Priya R.
Full-Stack Dev
Score +33pts

Finally a tool that explains WHY each fix matters. The INP breakdown simulator is genius — I've shared it with my whole team.

JK
Jordan K.
Performance Lead
INP ↓ 68%

Start Fixing Your Web Vitals Today

Join developers who've improved their Core Web Vitals scores and boosted their site rankings — 100% free.

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