Performance Metrics
The numbers don't lie. See how Astro's architecture translates to real-world performance gains.
Why Astro is Fast
This Site's Scores
Overall Lighthouse performance score
Semantic HTML and ARIA support
Modern web standards compliance
Search engine optimization
Loading Performance
When first content appears
When main content is visible
When page becomes interactive
Main thread blocking time
Visual stability score
How quickly content is visible
Framework Comparison
Framework Comparison
JS Bundle Size - Less is better
Note: These are representative values for typical content sites. Actual performance varies based on implementation, content, and optimization.
Core Web Vitals
Google's metrics for measuring user experience. Astro helps you achieve great scores by default.
LCP
Largest Contentful Paint
Measures loading performance. Should occur within 2.5 seconds.
INP
Interaction to Next Paint
Measures interactivity. Should be less than 200 milliseconds.
CLS
Cumulative Layout Shift
Measures visual stability. Should be less than 0.1.
How Astro Achieves This
Islands Architecture
Only interactive components ship JavaScript. A blog post with one interactive widget ships only that widget's JS, not the entire page.
Zero JS Default
Every component renders to HTML at build time. You explicitly opt-in to client-side JavaScript when you need interactivity.
Smart Hydration
Control exactly when components hydrate: immediately, when idle, when visible, or based on media queries. Load JS only when needed.
Optimized Build
Vite-powered builds with automatic code splitting, tree shaking, and asset optimization. Production bundles are minimal by design.
The Bottom Line
90%
Less JavaScript shipped
3x
Faster page loads
100
Lighthouse scores achievable
Performance isn't something you optimize for later—it's built into Astro's DNA.