Search engines no longer just look at keywords; they look at performance. If your site is slow, you are invisible to Google.
The New Kid: INP (Interaction to Next Paint)
INP has replaced FID as a key metric. It measures the latency of all interactions. Optimizing this requires minimizing main-thread work and ensuring your React components don't re-render unnecessarily.
Hydration Optimization
Next.js 15 partial prerendering is a game changer. It allows us to keep the static parts of your page fast while streaming in dynamic content, keeping your LCP (Largest Contentful Paint) below the 2-second gold standard.