ClaudePerformance
Web Performance Optimization Audit
Why this prompt matters
Performance audits without estimated impact lead to bikeshedding. Quantifying each improvement helps teams prioritize the highest-value optimizations.
What we use it for
Performance
Prompt
Audit this web page/application for performance issues. Analyze: 1) Critical rendering path, 2) JavaScript bundle size, 3) Image optimization opportunities, 4) Caching strategy, 5) Core Web Vitals impact. For each issue, estimate the improvement in milliseconds and provide the fix with code.
Result
## Performance Audit Results
### 1. Render-Blocking CSS (−800ms LCP)
**Issue**: 3 external stylesheets block first render
**Fix**: Inline critical CSS, async-load the rest:
```html
```
### 2. Unoptimized Images (−400ms LCP)
**Issue**: Hero image is 2.4MB PNG
**Fix**: Convert to WebP, add srcset:
```html
![]()
```
**Estimated Total Improvement**: 1.8s faster LCP
Performance audits without estimated impact lead to bikeshedding. Quantifying each improvement helps teams prioritize the highest-value optimizations.
This prompt demonstrates a structured approach to performance, producing consistent, high-quality results that can be iterated upon.