Web Performance in 2026: Core Web Vitals, Revisited

Lab scores lie. A page that hits 100 on Lighthouse can still feel slow on a mid-range Android on a spotty 4G connection — which is exactly what most of your users are on.

The Metrics That Matter Now

• LCP — the single biggest predictor of bounce
• INP — replaced FID and exposes real interaction latency
• CLS — still catches lazy image sizing
• TTFB — the ceiling on everything downstream

The Wins Nobody Talks About

• Ship one font weight, not four
• Preload the LCP image, don't lazy-load it
• Break up long tasks with scheduler.yield or setTimeout
• Serve modern image formats with correct sizes, not srcset theater

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Performance is not a project. It's a budget you defend every sprint.