Question 1

Do Web Vitals still matter in the AI era?

Accepted Answer

More than ever. AI-generated code often creates performance-heavy applications with excessive JavaScript, unoptimized assets, and inefficient patterns. Fast sites convert better and rank higher regardless of how they're built. We're developing an MCP integration to bring real performance data directly into AI coding assistants like Claude and Cursor.

Question 2

What are Core Web Vitals?

Accepted Answer

Core Web Vitals are a set of specific factors that Google considers important in a webpage's overall user experience. They include Largest Contentful Paint (LCP), Cumulative Layout Shift (CLS), and First Input Delay (FID). We also track additional metrics like First Contentful Paint (FCP) and Time to First Byte (TTFB) for comprehensive performance insights.

Question 3

How accurate is this analysis?

Accepted Answer

Our analysis uses real field data from Chrome User Experience Report (CrUX), which represents actual user experiences on your site. This field data provides a more accurate picture of real-world performance than synthetic lab tests, as it reflects the conditions your users actually experience.

Question 4

Why should I care about Web Vitals?

Accepted Answer

Web Vitals directly impact your site's search engine rankings, user experience, and conversion rates. Sites with better Web Vitals scores typically see higher engagement and better business outcomes.

Question 5

Can I analyze password-protected or internal sites?

Accepted Answer

Currently, our tool can only analyze publicly accessible websites since we rely on Chrome User Experience Report data. For internal or password-protected sites, we recommend using Sentry's Web Vitals monitoring, which can track Web Vitals and other performance metrics from within your application.

Question 6

How often should I check my Web Vitals?

Accepted Answer

We recommend checking your Web Vitals regularly, especially after making significant changes to your site. Monthly checks are good for most sites, while high-traffic sites might benefit from weekly monitoring.

Question 7

How do Web Vitals work with Progressive Web Apps (PWAs) and Single Page Applications (SPAs)?

Accepted Answer

Current Core Web Vitals metrics only capture initial page loads, not SPA route transitions. This means client-side navigation performance isn't reflected in CrUX data or traditional Web Vitals measurements. Chrome is experimenting with a Soft Navigations API that defines navigation by three heuristics: user action, URL change, and DOM change. This experimental feature (available in Chrome 139+ via origin trial) aims to measure LCP, CLS, and INP for individual route changes. Until this becomes standard, the best approach for PWAs is implementing real user monitoring with tools like Sentry's Web Vitals monitoring, which can track performance across all navigation types and provide comprehensive insights into your app's actual user experience.

Question 8

My site has good lab scores but bad field data - why?

Accepted Answer

Lab data from tools like Lighthouse uses simulated conditions, while field data from Chrome User Experience Report reflects real users with varying devices, networks, and browsers. Field data is more representative of actual user experience and what matters for SEO rankings.

Question 9

Can backend issues cause poor Web Vitals scores?

Accepted Answer

Absolutely. Poor database queries, excessive middleware, or slow server-side processing can significantly impact Time to First Byte (TTFB) and Largest Contentful Paint (LCP). Use application performance monitoring tools to trace performance issues through your entire stack.

Question 10

How do images affect Web Vitals beyond just load time?

Accepted Answer

Images impact multiple Core Web Vitals: oversized images hurt LCP, missing width/height attributes cause CLS, and even background images can contribute to layout shift. Use modern formats (WebP/AVIF), proper sizing, and lazy loading for below-the-fold content.

Question 11

What's on the roadmap for WebVitals?

Accepted Answer

We're actively developing several exciting features: In-depth Lighthouse analysis with actionable recommendations, historical data tracking to monitor performance trends over time, unique shareable URLs for easy collaboration, user accounts to persist and track results across sessions, competitive benchmarking against similar sites, performance budgets with automated alerts, CI/CD integration for continuous monitoring, multi-page site analysis, custom performance thresholds, API access for automation, exportable PDF reports, team collaboration features, and integrations with popular tools like GitHub and Slack. Follow our progress and request features through our feedback channels!

Core Web Vitals Analysis Tool

Live Web Vitals

Understanding Core Web Vitals

Largest Contentful Paint

Interaction to Next Paint

Cumulative Layout Shift

First Contentful Paint

Time to First Byte

Frequently Asked Questions