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web-performance-audit

This skill performs comprehensive web performance audits by measuring Core Web Vitals, identifying bottlenecks, and providing prioritized optimization recommendations to improve page load times and user experience.

Packaged view

This page reorganizes the original catalog entry around fit, installability, and workflow context first. The original raw source lives below.

Stars
84
Hot score
93
Updated
March 20, 2026
Overall rating
C5.0
Composite score
5.0
Best-practice grade
A92.0

Install command

npx @skill-hub/cli install secondsky-claude-skills-web-performance-audit

Repository

secondsky/claude-skills

Skill path: plugins/web-performance-audit/skills/web-performance-audit

This skill performs comprehensive web performance audits by measuring Core Web Vitals, identifying bottlenecks, and providing prioritized optimization recommendations to improve page load times and user experience.

Open repository

Best for

Primary workflow: Ship Full Stack.

Technical facets: Full Stack.

Target audience: everyone.

License: MIT.

Original source

Catalog source: SkillHub Club.

Repository owner: secondsky.

This is still a mirrored public skill entry. Review the repository before installing into production workflows.

What it helps with

  • Install web-performance-audit into Claude Code, Codex CLI, Gemini CLI, or OpenCode workflows
  • Review https://github.com/secondsky/claude-skills before adding web-performance-audit to shared team environments
  • Use web-performance-audit for development workflows

Works across

Claude CodeCodex CLIGemini CLIOpenCode

Favorites: 1.

Sub-skills: 0.

Aggregator: No.

Original source / Raw SKILL.md

---
name: web-performance-audit
description: Web performance audits with Core Web Vitals, bottleneck identification, optimization recommendations. Use for page load times, performance reviews, UX optimization, or encountering LCP, FID, CLS issues, resource blocking, render delays.
license: MIT
---

# Web Performance Audit

Conduct comprehensive performance audits and implement optimizations.

## Core Web Vitals Targets

| Metric | Good | Needs Improvement | Poor |
|--------|------|-------------------|------|
| LCP (Largest Contentful Paint) | <2.5s | 2.5-4s | >4s |
| FID (First Input Delay) | <100ms | 100-300ms | >300ms |
| CLS (Cumulative Layout Shift) | <0.1 | 0.1-0.25 | >0.25 |
| INP (Interaction to Next Paint) | <200ms | 200-500ms | >500ms |

## Performance Measurement

```javascript
// Using web-vitals library
import { getCLS, getFID, getLCP, getTTFB } from 'web-vitals';

function sendToAnalytics({ name, value, id }) {
  console.log({ name, value, id });
}

getCLS(sendToAnalytics);
getFID(sendToAnalytics);
getLCP(sendToAnalytics);
getTTFB(sendToAnalytics);
```

## Lighthouse Automation

```javascript
const lighthouse = require('lighthouse');
const chromeLauncher = require('chrome-launcher');

async function runAudit(url) {
  const chrome = await chromeLauncher.launch({ chromeFlags: ['--headless'] });
  const result = await lighthouse(url, {
    port: chrome.port,
    onlyCategories: ['performance']
  });

  await chrome.kill();
  return result.lhr;
}
```

## Optimization Strategies

### Quick Wins (1-2 days)
- Enable gzip/brotli compression
- Minify CSS/JS
- Defer non-critical scripts
- Optimize images (WebP, lazy loading)

### Medium Effort (1-2 weeks)
- Implement code splitting
- Add service worker caching
- Preload critical resources
- Eliminate render-blocking resources

### Long-term (1-3 months)
- Architecture improvements
- CDN optimization
- Database query optimization

## Performance Budget

```json
{
  "timings": [
    { "metric": "first-contentful-paint", "budget": 1500 },
    { "metric": "largest-contentful-paint", "budget": 2500 }
  ],
  "resourceSizes": [
    { "resourceType": "script", "budget": 150 },
    { "resourceType": "image", "budget": 300 }
  ]
}
```

## Audit Checklist

- [ ] Measure baseline Core Web Vitals
- [ ] Run Lighthouse audit (mobile & desktop)
- [ ] Analyze real user metrics (RUM)
- [ ] Identify largest contentful element
- [ ] Check for layout shifts
- [ ] Review JavaScript bundle size
- [ ] Test on slow 3G connection
- [ ] Set performance budget
- [ ] Configure monitoring alerts