What problem does it solve? Slow page loads usually stem from latency and round trips rather than bandwidth, and fixing them requires understanding how DNS, TCP, TLS, HTTP versions, caching layers, and the browser rendering pipeline actually interact. This Skill provides a systematic framework for diagnosing slow sites and applying the correct protocol, loading, caching, and rendering optimizations. ## Core Features & Use Cases - Six-domain performance framework: Covers network fundamentals (TCP/TLS handshakes, slow start, DNS), HTTP/1.1-to-HTTP/3 protocol evolution, critical rendering path, caching strategies, Core Web Vitals (LCP, INP, CLS), and real-time transports (WebSocket vs SSE vs long polling). - Quick Diagnostic scorecard: Eight pass/fail checks (TTFB, LCP, INP, CLS, content hashing, HTTP/2+, render-blocking resources, compression) produce a 0-10 score with a specific fix for each failure. - Deep reference guides: Five reference documents provide copy-paste configurations such as Nginx OCSP stapling, service worker cache-first/network-first recipes, WebSocket reconnection with exponential backoff, and resource hint ordering. - Use Case: A user reports their e-commerce site feels slow on mobile. Run the Quick Diagnostic, find LCP at 4.2s and no content hashing, then apply the LCP preload pattern with fetchpriority="high" and immutable cache headers for hashed static assets. ## Quick Start Ask the assistant to run the web performance diagnostic on your site and explain which of the eight checks fail and how to fix each one.
