Google PageSpeed Insights - A free tool by Google for analyzing and improving website performance.

## Definition of Google PageSpeed Insights Google PageSpeed Insights is a free tool developed by Google to analyze website performance. It generates reports with lab data (simulated testing via Lighthouse) and field data (real-user metrics from Chrome UX Report) to identify optimization opportunities for loading speed and user experience. ## Data Types in PageSpeed Insights PageSpeed Insights provides two data types: 1. **Lab Data**: Collected through Lighthouse in controlled environments, measuring performance, accessibility, SEO, and best practices. 2. **Field Data**: Real-user metrics from CrUX (Chrome UX Report), including FCP, LCP, CLS, INP, and TTFB over a 28-day period. ## Performance Scoring System PageSpeed Insights uses a three-tier scoring system for Core Web Vitals: - **Good (Green)**: FCP ≤1.8s, LCP ≤2.5s, CLS ≤0.1, INP ≤200ms, TTFB ≤800ms. - **Needs Improvement (Yellow)**: FCP 1.8-3s, LCP 2.5-4s, CLS 0.1-0.25, INP 200-500ms, TTFB 800-1800ms. - **Poor (Red)**: Exceeds upper thresholds of "Needs Improvement." ## Key Features - Cross-device analysis (mobile/desktop) - Specific optimization recommendations (e.g., image compression, render-blocking resource removal) - API integration for automated testing (25,000 daily queries) - Daily-updated field data from CrUX ## Access Method Users can: 1. Visit [pagespeed.web.dev](https://pagespeed.web.dev/) and enter a URL. 2. Use the PageSpeed Insights API for automated testing in development workflows. Note: Only publicly accessible URLs are supported; localhost requires Lighthouse plugins. ## Core Web Vitals Metrics PageSpeed Insights evaluates these key metrics: - **FCP (First Contentful Paint)**: Time until first content appears. - **LCP (Largest Contentful Paint)**: Loading performance of main content. - **CLS (Cumulative Layout Shift)**: Visual stability score. - **INP (Interaction to Next Paint)**: Responsiveness to user inputs. - **TTFB (Time to First Byte)**: Server response speed (experimental). ## Advanced Usage Beyond manual testing, PageSpeed Insights offers API integration for continuous performance monitoring. For example, VRBO uses the API to track long-term trends. Field data updates daily, unlike monthly BigQuery exports, enabling near-real-time analysis. ### Citation sources: - [Google PageSpeed Insights](https://pagespeed.web.dev) - Official URL Updated: 2025-04-01