LCP 3.0s -> 1.7s by re-encoding one image A real-estate listing page LCP was a 1.4MB hero JPEG served at 2400px into a 720px slot. — Resized to 2x display width (1440px), encoded AVIF: 1,400KB -> 96KB…
CLS 0.31 -> 0.02 on a magazine layout CLS = Cumulative Layout Shift. A web font swapped in 600ms after paint and reflowed every headline. — Measured: 0.24 of the 0.31 shift came from the font swap, 0.…
FCP 2.8s -> 1.1s by killing render-blocking CSS A blog loaded a 142KB framework stylesheet in <head>, blocking First Contentful Paint until the full file parsed. — Critical CSS (above-the-fold, …
INP 480ms -> 150ms on an e-commerce PLP INP = Interaction to Next Paint, the p75 latency of clicks/taps. The 'add to cart' click ran a synchronous 220ms recommendation recompute on the main thread. — …
JS bundle 612KB -> 188KB on a B2B dashboard Main bundle shipped a whole date library, a charting lib, and an icon set fully imported. — moment.js (231KB) -> date-fns with 3 functions (8KB). — Icon fon…
TTFB 820ms -> 90ms on a SaaS marketing site TTFB = time to first byte. Every page was rendered server-side per request on a single origin in Virginia. — EU p75 TTFB was 1,140ms (extra round trips + co…
