Client Hints (Sec-CH-DPR, Sec-CH-Width, Critical-CH) let your CDN pick byte-perfect image sizes in 2026. Practical setup, worker code, and real LCP wins from a Chrome-heavy audit.
Learn how RFC 9211's Cache-Status header exposes hits, misses, forwards, and coalesced requests across your CDN chain. Includes vendor mapping and TTFB attribution patterns.
Tag any image, price, or button with elementtiming and read its real paint timestamp from PerformanceObserver. Practical RUM setup, cross-origin gotchas, and the new Container Timing trial.
Break down Time to First Byte into named backend phases with the Server-Timing header. Includes syntax, CORS gotchas, Node/Workers/nginx examples, and RUM integration.
Fix Cumulative Layout Shift fast: capture per-element attribution with web-vitals, replay shifts in Chrome DevTools, and ship one-line fixes for the five sources that cause 90% of real CLS.
A practical 2026 guide to the four browser resource hints (preload, prefetch, preconnect, dns-prefetch): when each one helps, when it hurts LCP, and the exact decision flow to pick the right one.
How to use the stale-while-revalidate Cache-Control directive to serve cached responses instantly while revalidating in the background. RFC 5861 recipes, CDN support in 2026, and footguns to avoid.
Cross-document View Transitions let MPAs animate between pages like SPAs, opt in via one CSS rule. Real-world setup, named elements, Speculation Rules pairing, and Core Web Vitals impact from production.
The Service Worker Static Routing API lets the browser bypass your SW fetch handler for chosen URLs, cutting cold-start latency and LCP. Hands-on guide with 2026 examples, Workbox interop, browser support, and the diagnostics I use to prove the win.
How I shipped a production scheduler.yield fallback for Safari in 2026 using postTask and MessageChannel, kept Chrome's INP wins, and avoided the setTimeout(0) clamp tax.
A field-tested walkthrough of the seven WordPress plugin patterns that push INP past 500ms in 2026, with a defer-and-idle JavaScript fix you can ship today without uninstalling anything.
INP became a Core Web Vital in March 2024, and most of us reached for the same tools we'd been using for FID. For the trickier regressions you'll stare at clean traces and lose a week.