A review skill that catches front-end performance regressions before they reach users.
What it covers
- Core Web Vitals — LCP optimization, CLS prevention, INP/FID reduction strategies
- Bundle size — tree-shaking effectiveness, code splitting boundaries, dynamic imports for heavy modules
- Image optimization — modern formats (WebP/AVIF), responsive srcset, lazy loading below the fold
- Rendering — avoiding layout thrashing, requestAnimationFrame for visual updates, virtualization for long lists
- Network — resource hints (preload/prefetch), HTTP caching headers, minimizing waterfall chains
- JavaScript cost — main thread blocking, Web Worker offloading, avoiding synchronous heavy computation
When to use
Run this on PRs that add new dependencies, modify page layouts, or change data-fetching patterns. Essential before major launches where performance directly affects business metrics.