#core-web-vitals

#core-web-vitals

Today's users expect fast, smooth experiences by default. Performance is no longer just a "nice to have"; it's a real product advantage that directly impacts retention, conversions, and revenue. The challenge is that debugging performance issues can feel overwhelming because there are so many reasons an app might be slow. In this guide, I'll share a step-by-step framework for optimizing React apps from bundle analysis all the way to server-side rendering.

Slow pages frustrate visitors, increasing bounce rates and reducing conversions, while fast-loading sites enhance engagement, mobile experience, and revenue potential. Page load improvement involves compressing files, caching assets, and minimizing code, all contributing to performance gains that retain users and satisfy search algorithms. Beyond technical tweaks, user-centric strategies such as lazy loading and prioritizing above-the-fold content ensure visitors experience immediate value without waiting for every element to render.

That said, the Core Web Vitals metrics that Google uses as a ranking factor are a great starting point, as they cover different aspects of visitor experience: Largest Contentful Paint (LCP): Measures the initial page load time. Cumulative Layout Shift (CLS): Measures if content is stable after rendering. Interaction to Next Paint (INP): Measures how quickly the page responds to user input.

CrUX measures page loads and the Core Web Vitals number is the 75th percentile of those page loads.

Google Merchant API will replace the Content API for Shopping within the next year, signaling significant changes for e-commerce integration with Google services.