Performance work used to be the thing front-end teams did "if there was time left." In 2026 it is table stakes. Core Web Vitals are a confirmed Google ranking input, and real users bounce from anything that feels sluggish on a mid-range Android phone over a flaky mobile connection.
This is the checklist I keep coming back to when I audit a site. It is written for developers, but every item also moves the SEO needle — which is exactly why performance and search visibility have stopped being two separate conversations.
The three metrics that actually matter
Largest Contentful Paint (LCP) — aim for under 2.5s. This is almost always your hero image or main headline. Quick wins: serve correctly sized images in AVIF/WebP, add fetchpriority="high" to the LCP image, preload the hero font, and remove render-blocking CSS from the critical path.
Interaction to Next Paint (INP) — aim for under 200ms. INP replaced First Input Delay in 2024 and it is far less forgiving. It measures the latency of every interaction on the page, not just the first one. Wins: break up long tasks, yield back to the main thread, debounce expensive handlers, and push non-urgent work into requestIdleCallback or a web worker.
