The fetchpriority attribute is one of the most precise tools for shaping browser resource loading. Used right, it can shave 200-800ms off your LCP without touching CSS or JavaScript. Here's every legitimate use case, the mistakes that quietly hurt performance, and how to measure real-world impact.
Set up production Real User Monitoring with Google's web-vitals v4 library. Capture LCP, INP, and CLS attribution data, build a custom collection endpoint, sample smartly, and reconcile field data with Lighthouse — every step with working 2026 code.
Learn how to use the Long Animation Frames (LoAF) API to diagnose and fix slow INP interactions. Covers script attribution, rendering phase breakdowns, third-party impact analysis, and production reporting.
Learn how to define performance budgets and enforce them with Lighthouse CI in GitHub Actions. Catch regressions automatically with budget.json config, lighthouserc.js setup, and real-world thresholds for e-commerce, blogs, and SaaS dashboards.
Learn how to optimize your site for the browser's back/forward cache (bfcache) to achieve instant back navigation, improve Core Web Vitals, and fix common blockers like unload events and Cache-Control headers.
Learn how to implement the View Transitions API for smooth, GPU-accelerated page transitions in both SPAs and MPAs. Covers cross-document transitions, Speculation Rules integration, Core Web Vitals impact, and a full performance checklist.
Learn how the CSS content-visibility property can cut rendering time by up to 80%. Covers content-visibility: auto for deferred rendering, contain-intrinsic-size for preventing layout shifts, SPA view caching, and Chrome DevTools profiling to verify real gains.
Learn how to fix render-blocking CSS using critical CSS extraction, the media print swap technique, and tools like Beasties. Covers automated extraction, unused CSS removal with PurgeCSS, and framework integration for Next.js, Nuxt, and Astro.
Third-party scripts silently kill your site speed. Learn how to audit every external script, measure its real cost, and fix it — from simple async/defer changes to advanced techniques like Partytown web workers and server-side GTM tagging.
Web fonts silently degrade LCP, CLS, and FCP. Learn every optimization layer — WOFF2, variable fonts, subsetting, font-display strategies, CSS metric overrides, preloading, and self-hosting — with working code for each technique.
A hands-on guide to diagnosing and fixing Interaction to Next Paint (INP) issues. Covers all three phases, the LoAF API, framework-specific strategies for React, Vue, and Angular, Web Workers, and production monitoring.