--- title: "Web Performance and Core Web Vitals: Audit, Optimization, and Monitoring" description: "Boost your speed, SEO, and conversions. Web Performance 360 Audit, Core Web Vitals Optimization (LCP, INP, CLS), and Advanced CrUX Monitoring." url: https://edgeangel.co/en/data-foundations/web-performance lang: en --- > Site index for agents, read it before exploring further : https://edgeangel.co/llms.txt > Canonical HTML page, which also carries the diagrams and visuals : https://edgeangel.co/en/data-foundations/web-performance # Web Performance Don't let speed slow down your growth A slow page means lost revenue. With EdgeAngel, audit, optimize, and monitor your Core Web Vitals (LCP, INP, CLS) for a healthy site: fluid experience, boosted SEO, and optimized crawl for AIs (GEO). [Request an Audit](https://edgeangel.co/en/data-foundations/web-performance#contact) Advanced Setup GDPR Compliance Ongoing Support ## Your site's vitality, measured by real users Core Web Vitals Real User Metrics (CrUX) PASSING 1.2s LCP GOOD 180ms INP GOOD 0.05 CLS GOOD Desktop & Mobile Last 28 days Performance 98/100 Speed Index 0.8s Web Performance isn't just a technical issue, it's a major business stake. We support you in moving from a 'Lighthouse Checklist' approach to a true user experience strategy: **Reality-Based Audit (CrUX)** We analyze data from your real visitors (Chrome UX Report), the only metrics that count for Google (SEO) and your conversion rate. **Technical Optimization & Coaching** We don't just do audits, we work with your developers (React, Next.js, Magento...) to implement fixes: lazy loading, image formats, third-party script management. **Data-Driven Monitoring** No more manual tests. We deploy automated Dashboards connected to the CrUX API and BigQuery to track your speed KPIs just like your business KPIs. **Performance Culture** We help your marketing and tech teams align their objectives: adding a feature or tag should never come at the expense of user experience. [Explorer nos services](https://edgeangel.co/en/data-foundations/web-performance#services-nav) Core Web Vitals Real User Metrics (CrUX) PASSING 1.2s LCP GOOD 180ms INP GOOD 0.05 CLS GOOD Desktop & Mobile Last 28 days Performance 98/100 Speed Index 0.8s Demo App ## Monitor your Core Web Vitals in real-time Discover our advanced monitoring solution. Connected to the CrUX API and BigQuery, it gives you a clear, historical, and granular view of your key pages' performance. Demo Client - CWVDemo Client - Web Performance - Core Web Vitals Select Page:Home PageCategory PageProduct PageCheckout Page Viewing historical data for: https://www.demo-client.com/ ### Home Page : https://www.demo-client.com/ Mobile ### Home Page : https://www.demo-client.com/ Desktop \* Interactive demo data. Try switching tabs! ### Nos Certifications ## They trust us ## Our Web Performance Offer A to Z support: from technical audit to continuous optimization of your Core Web Vitals. 01 / 03 - 01 ### Web Performance 360 Audit A complete diagnosis to validate the current level of your web performance (Core Web Vitals) and identify conversion blockers. - CrUX Analysis (Real User Metrics): Analysis of your real users' experience (Chrome UX Report) regarding performance, rather than bot simulations (Lighthouse), for a realistic view. - Core Web Vitals Study: In-depth audit of Google metrics (LCP, INP, CLS) on Mobile and Desktop to identify critical pages (Home, PLP, PDP). - Technical Analysis: Identification of blocking resources (JS, CSS, Third-parties), asset weight, and loading issues (Waterfall analysis). - Business & UX Impact: Correlation between load times and your bounce or conversion rates to prioritize high ROI initiatives. - 02 ### Optimization & Dev Coaching Concrete actions and support for your technical teams to sustainably optimize your site (Next.js, React, CMS...). - Developer Workshops: Skills transfer and co-construction of the optimization roadmap (Lazy loading, WebP/AVIF formats, Code splitting). - Third-Party Script Management: Optimization of partner tag loading (GTM, Didomi, A/B Test) to limit impact on load time (Defer, Async, Server-Side). - Infrastructure Optimization: Recommendations on CDN, caching, and resource compression to serve your content instantly (e.g., serving from Los Angeles vs Edge). - Quick Wins: Immediate implementation of high-impact fixes identified during the audit for quick gains on Core Web Vitals. - 03 ### Monitoring & Alerting Implementation of a control tower to continuously monitor your performance and be alerted to regressions before they impact your business. - CrUX Data Studio Dashboard: Creation of automated dashboards based on real data (CrUX API + BigQuery) to track the evolution of your LCP, INP, CLS scores. - Automated Alerting: Configuration of alerts (Email, Slack) in case of sudden performance degradation (e.g., after a production release or script addition). - Modern Data Stack: Centralization of performance data in your Data Warehouse (BigQuery) to cross-reference web perf and business data (GA4). - Competitive Tracking: Continuous benchmarking of your speed against market leaders. 01 ### Web Performance 360 Audit A complete diagnosis to validate the current level of your web performance (Core Web Vitals) and identify conversion blockers. - CrUX Analysis (Real User Metrics): Analysis of your real users' experience (Chrome UX Report) regarding performance, rather than bot simulations (Lighthouse), for a realistic view. - Core Web Vitals Study: In-depth audit of Google metrics (LCP, INP, CLS) on Mobile and Desktop to identify critical pages (Home, PLP, PDP). - Technical Analysis: Identification of blocking resources (JS, CSS, Third-parties), asset weight, and loading issues (Waterfall analysis). - Business & UX Impact: Correlation between load times and your bounce or conversion rates to prioritize high ROI initiatives. We are an independent agency founded by experts with one ambition: **deliver value quickly through Web Performance and data.** 01. ### Tech & UX Expertise Web performance doesn't stop at code. It directly impacts user experience, SEO, and your conversion rates. Our experts master the entire chain: from technical audit (Lighthouse, Waterfall) to framework optimization (Next.js, React) and third-party management (Tag Management). 02. ### Advanced Modern Data Stack Mastery We don't just do PDF audits. We industrialize performance monitoring. Automated collection of real user data (CrUX API), centralization in your Data Warehouse (BigQuery), and custom visualization (Data Studio) to pilot speed as a business KPI. 03. ### Tailored Support Every site is unique. We adapt our recommendations to your technical and organizational context. No "rebuild everything". We prioritize "Quick Wins" with high impact and support your technical teams in upskilling and adopting Web Perf best practices. ## Your Web Performance & Architecture Experts - ### Olivier Chubilleau CEO & Co-Founder Expert in Data & Analytics architectures, Olivier helps companies transform their approach to Web Performance into a business growth lever, combining technical and strategic vision. - ### Mathieu Lima Head of Collection Lead of collection at EdgeAngel, Mathieu masters the technical workings of Web Performance (Lighthouse, CrUX, DevTools) and supports tech teams in fine-tuning code optimization. ## Ready to accelerate your growth ? Let's discuss your data and marketing challenges. We'll respond within 24 hours. ### Paul Schmitt Consulting Director "Our goal is to make your data actionable to generate concrete value, quickly." [Or call us directly: +33 1 84 16 42 20](tel:+33184164220) ## Nos notes d'experts sur le sujet [ Note d'expert ### Web Performance & Modern Data Stack Web performance isn't just a technical checkbox. Discover how to monitor Core Web Vitals continuously with a Modern Data Stack approach (CrUX + BigQuery). Lire la note → ](https://edgeangel.co/en/notes/web-performance-modern-data-stack)[ Note d'expert ### Server-side Tagging with Google Tag Manager What is GTM Server-side? How does Server-Side Tagging integrate into your collection setup? What are the concrete advantages and current limitations? Lire la note → ](https://edgeangel.co/en/notes/server-side-tagging-avec-google-tag-manager) ## Frequently Asked Questions Lighthouse simulates a visit under ideal (or degraded) laboratory conditions ('Lab Data'), which is useful for debugging but does not reflect reality. CrUX (Chrome UX Report) gathers data from REAL users ('Field Data') browsing your site. It is the only metric Google uses for its SEO ranking (Core Web Vitals). Since Google's 'Page Experience' update, Core Web Vitals (LCP, INP, CLS) have become an official ranking factor. A slow or unstable site will be penalized in search results, especially on mobile. Optimizing your core web vitals is therefore essential to maintain and improve your SEO positions. A one-off audit is not enough. Site updates, adding marketing tags, or browser changes can degrade your stats. We recommend implementing continuous monitoring via the CrUX API connected to a Dashboard (Data Studio), coupled with an alerting system to react immediately in case of regression. It's classic! You probably test with a fiber connection and a powerful computer (MacBook Pro). Your users might have mid-range phones and unstable 4G. Google judges your site on the experience of ALL your visitors (the 75th percentile of CrUX data). That's why optimization must target the real user, not the developer. INP replaced FID (First Input Delay) in March 2024. It measures the overall responsiveness of your page to all interactions (clicks, taps, key presses). A poor INP score means your site 'freezes' or takes time to react when the user clicks, creating major frustration and increasing bounce rates. GTM itself is very lightweight, but the tags it fires can be heavy! If you load 50 third-party scripts (hotjar, chat, FB pixels...) at page start, your performance will drop. We optimize tag firing (smart triggers, prioritization) and migrate what is possible to Server-Side (sGTM) to lighten the user's browser. Yes, a critical role. If your server takes 1 second to respond (TTFB), even the most optimized code won't save your LCP. Using a CDN (like Cloudflare) allows serving your resources (images, CSS, JS) from a server close to the user, reducing latency. We also audit your infrastructure to ensure compression (Brotli/Gzip) and cache management are optimal. LCP (Largest Contentful Paint) measures SPEED: when does the main element of the page (image, title) display? CLS (Cumulative Layout Shift) measures STABILITY: does the page move during loading (buttons jumping, text shifting)? Both are essential: one for waiting, the other for frustration. [Contactez nos experts](https://edgeangel.co/en/data-foundations/web-performance#contact) ## Discover our other expertise A complete suite of tools to master your data [ ### Log Analysis Analyze your server logs to understand how Google crawls your site. Learn more ](https://edgeangel.co/en/performance-acquisition/log-analysis)[ ### SEO & GEO Markup Structure your data for SEO and answer engines (GEO). Learn more ](https://edgeangel.co/en/performance-acquisition/seo-geo-markup)[ ### SEO & GEO Tracking Track your rankings on strategic and generative keywords. Learn more ](https://edgeangel.co/en/performance-acquisition/seo-geo-tracking)[ ### Google Analytics The web analytics standard to measure your conversions. Learn more ](https://edgeangel.co/en/data-foundations/google-analytics) ```json {"@context":"https://schema.org","@type":"Organization","name":"EdgeAngel","url":"https://edgeangel.co","logo":"https://edgeangel.co/assets/brand/edgeangel-logo.svg","sameAs":["https://www.linkedin.com/company/edgeangel"],"contactPoint":{"@type":"ContactPoint","email":"hello@edgeangel.co","telephone":"+33 1 84 16 42 20","contactType":"customer service"}} {"@context":"https://schema.org","@type":"Service","name":"Web Performance and Core Web Vitals: Audit, Optimization, and Monitoring","description":"Boost your speed, SEO, and conversions. Web Performance 360 Audit, Core Web Vitals Optimization (LCP, INP, CLS), and Advanced CrUX Monitoring.","provider":{"@type":"Organization","name":"EdgeAngel","url":"https://edgeangel.co"},"areaServed":"France","url":"https://edgeangel.co/en/data-foundations/web-performance"} {"@context":"https://schema.org","@type":"FAQPage","mainEntity":[{"@type":"Question","name":"Why use CrUX data rather than Lighthouse?","acceptedAnswer":{"@type":"Answer","text":"Lighthouse simulates a visit under ideal (or degraded) laboratory conditions ('Lab Data'), which is useful for debugging but does not reflect reality. CrUX (Chrome UX Report) gathers data from REAL users ('Field Data') browsing your site. It is the only metric Google uses for its SEO ranking (Core Web Vitals)."}},{"@type":"Question","name":"What is the impact of Web Performance on SEO?","acceptedAnswer":{"@type":"Answer","text":"Since Google's 'Page Experience' update, Core Web Vitals (LCP, INP, CLS) have become an official ranking factor. A slow or unstable site will be penalized in search results, especially on mobile. Optimizing your core web vitals is therefore essential to maintain and improve your SEO positions."}},{"@type":"Question","name":"How to monitor Web Performance over the long term?","acceptedAnswer":{"@type":"Answer","text":"A one-off audit is not enough. Site updates, adding marketing tags, or browser changes can degrade your stats. We recommend implementing continuous monitoring via the CrUX API connected to a Dashboard (Data Studio), coupled with an alerting system to react immediately in case of regression."}},{"@type":"Question","name":"Why is my site fast for me but the score is bad?","acceptedAnswer":{"@type":"Answer","text":"It's classic! You probably test with a fiber connection and a powerful computer (MacBook Pro). Your users might have mid-range phones and unstable 4G. Google judges your site on the experience of ALL your visitors (the 75th percentile of CrUX data). That's why optimization must target the real user, not the developer."}},{"@type":"Question","name":"What is INP (Interaction to Next Paint)?","acceptedAnswer":{"@type":"Answer","text":"INP replaced FID (First Input Delay) in March 2024. It measures the overall responsiveness of your page to all interactions (clicks, taps, key presses). A poor INP score means your site 'freezes' or takes time to react when the user clicks, creating major frustration and increasing bounce rates."}},{"@type":"Question","name":"Does GTM (Google Tag Manager) slow down my site?","acceptedAnswer":{"@type":"Answer","text":"GTM itself is very lightweight, but the tags it fires can be heavy! If you load 50 third-party scripts (hotjar, chat, FB pixels...) at page start, your performance will drop. We optimize tag firing (smart triggers, prioritization) and migrate what is possible to Server-Side (sGTM) to lighten the user's browser."}},{"@type":"Question","name":"Do hosting and CDN play a major role?","acceptedAnswer":{"@type":"Answer","text":"Yes, a critical role. If your server takes 1 second to respond (TTFB), even the most optimized code won't save your LCP. Using a CDN (like Cloudflare) allows serving your resources (images, CSS, JS) from a server close to the user, reducing latency. We also audit your infrastructure to ensure compression (Brotli/Gzip) and cache management are optimal."}},{"@type":"Question","name":"What is the difference between LCP and CLS?","acceptedAnswer":{"@type":"Answer","text":"LCP (Largest Contentful Paint) measures SPEED: when does the main element of the page (image, title) display? CLS (Cumulative Layout Shift) measures STABILITY: does the page move during loading (buttons jumping, text shifting)? Both are essential: one for waiting, the other for frustration."}}]} ```