Google has used Core Web Vitals as a ranking signal since 2021. Most London business websites still fail the test, which means they rank below faster competitors even if their content is stronger.
01
LCP (Largest Contentful Paint) measures how fast the main content loads. CLS (Cumulative Layout Shift) measures visual stability. INP (Interaction to Next Paint) measures responsiveness. A pass requires all three to score green. Most WordPress sites with heavy themes and unoptimised images fail LCP.
02
WordPress themes load dozens of CSS files, scripts and plugins before showing anything. Wix and Squarespace have improved but still carry rendering overhead. A Next.js static site loads pre-built HTML with minimal JavaScript, which produces consistently faster scores.
03
Every site we build in Next.js with Cloudflare Pages delivery scores green on all three Core Web Vitals in production. We verify with PageSpeed Insights and WebPageTest before handover. If a site we built fails within three months of launch, we fix it without charge.
04
There are two numbers worth understanding, and confusing them costs businesses time. A PageSpeed Insights lab test runs in a controlled environment and gives you an instant diagnostic. The field data, drawn from the Chrome User Experience Report, reflects how your actual visitors experience the site over the previous 28 days on their own devices and networks. Google ranks on the field data, not the lab score, which is why a site that looks fine on a developer's fast connection can still fail for real London users on mid-range phones. We build for the field number from the start, then verify with both PageSpeed Insights and WebPageTest before handover so the score you pass is the one Google actually measures.
05
When a WordPress site fails Core Web Vitals, the usual response is to install a caching or optimisation plugin and hope. It rarely holds. Those plugins paper over a render path that is fundamentally heavy: a theme loading dozens of stylesheets, render-blocking scripts and a database query on every visit. You might claw back a few points, but the next plugin update, theme change or new section often undoes it, and you are back to chasing the same problem. A bespoke Next.js rebuild removes the cause rather than masking it by shipping pre-built HTML with minimal JavaScript. That is why every site we deliver scores green in production and stays green over time, because the underlying cause is gone rather than masked.
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