Engineering lab
Interactive demos that explain Core Web Vitals, optimization techniques, and how I think about slow LCP—without fabricating production Lighthouse scores.
All metrics on this page are demo / simulated teaching aids unless a future version wires live measurement APIs.
Illustrative vitals for teaching—not claimed production Lighthouse results.
LCP
1.4s
Largest Contentful Paint
When the main content finishes painting.
FCP
0.9s
First Contentful Paint
When the first text or image appears.
CLS
0.04
Cumulative Layout Shift
Visual stability — lower is better.
INP
120ms
Interaction to Next Paint
Responsiveness to user input.
Toggle a simulated optimization outcome. Values are teaching examples, not a live audit of this site.
LCP
3.2s
FCP
1.8s
JS
420 KB