Performance
Make sure your app is fast enough for users — because speed affects experience and conversion.
Run this audit when preparing for launch, after major changes, or when users report slowness.
Useful for developers and product managers tracking quality.
Why This Matters
Slow apps frustrate users and hurt business metrics. Studies show that every second of delay reduces conversions. Users expect pages to load quickly and respond instantly to their actions. Performance isn't just technical — it directly affects user satisfaction and success.
What to Check
Focus on these four areas when reviewing performance:
Page Load Speed
How fast does the page appear? Check that the main content loads within 2.5 seconds. Test on real devices and slow connections, not just your fast development machine.
Interactivity
How fast does it respond to clicks? Buttons and inputs should respond within 200 milliseconds. Users shouldn't wonder if their click was registered.
Images & Assets
Are images optimized? Use modern formats (WebP), proper sizing, and lazy loading for images below the fold. Oversized images are the most common performance problem.
Runtime Efficiency
Does it stay fast while using it? Check for memory leaks, unnecessary re-renders, and slow database queries that degrade performance over time.
Stage Expectations
What performance standards apply at each stage:
Skip
Speed doesn't matter yet. Focus on proving the idea works.
Light
Measure baseline metrics. Fix obvious issues that block usage.
Full
Core Web Vitals passing. Performance budget defined and respected.
Complete
Actively monitored. Regression alerts in place. Continuously optimized.
Core Web Vitals Targets
Google's metrics for measuring user experience:
LCP (Largest Contentful Paint)
Main content visible: < 2.5s is good
INP (Interaction to Next Paint)
Response to clicks: < 200ms is good
CLS (Cumulative Layout Shift)
Visual stability: < 0.1 is good
Common Issues
Page loads slowly
Optimize images, lazy load below-the-fold content, reduce JavaScript bundle size
Layout jumps around while loading
Set explicit dimensions on images and dynamic content areas
Clicks feel slow to respond
Reduce JavaScript on the main thread, use code splitting for large features
App gets slower over time
Check for memory leaks in effects, remove event listeners when components unmount
Database queries are slow
Add indexes, avoid N+1 queries, implement caching for frequently accessed data
Run with AI: Use /audit performance to have an AI agent check your codebase for performance issues. The agent will analyze images, bundle size, database queries, and React rendering patterns.
Next Steps
Continue your quality review: