AcuityScan

Performance Scan

Test your website's speed from both desktop and mobile perspectives. Get separate Lighthouse scores, Core Web Vitals, and actionable optimization recommendations.

Desktop + Mobile scoresCore Web VitalsGoogle Lighthouse60+ tech detection

What you get

Here's a sample of what a performance scan returns.

Desktop vs Mobile Scores

Separate Lighthouse scores for each platform. Desktop typically scores higher — mobile has slower CPU simulation and stricter thresholds.

Core Web Vitals

LCP (loading), FCP (first paint), CLS (visual stability), TBT (interactivity), and TTFB (server response). These are the metrics Google uses for search ranking.

Optimization Issues

Every finding includes severity, business impact, and specific fix instructions. From render-blocking scripts to unoptimized images.

Technology Detection

Identifies 60+ technologies in your stack — CMS, frameworks, analytics, CDN, hosting, fonts, and more. Helps diagnose what's slowing you down.

How it works

Google Lighthouse

We run Google's Lighthouse engine against your site from their servers — the same test behind Chrome DevTools' Lighthouse tab. Separate runs for desktop and mobile.

Server-Side Checks

We measure TTFB, check compression (gzip/brotli), detect CDN usage, analyze cache headers, and inventory third-party scripts independently of Lighthouse.

Technology Detection

We scan your page for signatures of 60+ technologies — CMS platforms, JavaScript frameworks, analytics tools, CDN providers, hosting, and more.

Image Analysis

Every image is checked for lazy loading, modern formats (WebP/AVIF), appropriate sizing, and whether it's render-blocking.

Chrome UX Report

When available, we pull real-user data from Google's Chrome UX Report (CrUX) — actual field metrics from Chrome users visiting your site.

Weighted Scoring

The combined score weights mobile at 60% and desktop at 40%, reflecting Google's mobile-first indexing. Both scores are shown separately so you can prioritize.

Better than the alternatives

FeatureAcuityScanGTmetrixPageSpeed Insights
Desktop + MobileBoth, side by sideOne at a timeOne at a time
Core Web VitalsAll 5 metricsAll 5All 5
Fix instructionsCopy-paste codeBasic tipsBasic tips
Tech detection60+ technologiesNoNo
Full site auditPart of 350+ check Performance onlyPerformance only
This toolFree, unlimitedFree tier (limited)Free
Site monitoring (full scan)From $29/moFrom $25/mo—

Common questions

Why are desktop and mobile scores different?
Google Lighthouse simulates a mid-tier mobile device with a slower CPU and throttled network for mobile tests. Desktop tests use faster settings. Most sites score 10-30 points higher on desktop.
Which score matters more?
Mobile. Google uses mobile-first indexing, meaning your mobile performance directly affects search rankings. Our combined score weights mobile at 60% for this reason.
Why does my score change between scans?
Performance scores depend on real-time factors — server load, third-party script response times, CDN caching state, and network conditions. Variations of 3-5 points are normal.
What are Core Web Vitals?
Three metrics Google uses for ranking: LCP (Largest Contentful Paint — how fast your main content loads), CLS (Cumulative Layout Shift — how much the page moves during loading), and INP/TBT (how responsive the page is to interaction). We also show FCP and TTFB.
Do I need an account?
No account required. For unlimited scans, monitoring, white-label reports, and the full Site+ Scan, see our Pro plan at $29/month.
How is this different from Chrome DevTools?
Same Lighthouse engine, but we run it from Google's servers (not your local machine), test both desktop and mobile in one click, add tech stack detection, and provide fix instructions you can copy-paste.

Related tools

Tech LookupThreat CheckHTTP HeadersAccessibility Check

Want the full picture?

The checks performance plus 7 other categories — email, DNS, SSL, SEO, accessibility, privacy, and mobile.

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