v1.0.0
Reviews front-end code for performance — Core Web Vitals, lazy loading, image optimization, bundle size, and rendering efficiency. Performance directly impacts conversion rates and search rankings, but degradation happens gradually and is easy to miss in development.
A review skill that catches front-end performance regressions before they reach users.
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.
Lazy-load images, components, and data that are below the initial viewport fold. Loading everything upfront makes the user wait for content they haven't scrolled to yet — increasing Time to Interactive and burning mobile data on content the user may never see.
Serve images in modern formats (WebP/AVIF), at appropriate dimensions, and with width/height attributes. Unoptimized images are typically the largest assets on a page — a single uncompressed hero image can be larger than all your JavaScript combined, destroying load times on mobile.
Audit and minimize third-party scripts (analytics, chat widgets, ad trackers). Each third-party script adds DNS lookups, TLS handshakes, and JavaScript execution that blocks the main thread — a single chat widget can add 500ms+ to page load and degrade Core Web Vitals scores.
BeforeMerge scans your pull requests against all 3 Web Performance Review rules automatically. Get actionable feedback before code ships.