Performance Audit

A real lab performance audit, desktop and mobile

LCP, CLS, TBT, Speed Index, and TTFB, measured on both a desktop profile and a 375px mobile viewport - with fixes written for the framework Scanverra detects on your page.

Run free performance audit

Every metric, measured

The six signals that make up your performance score.

Largest Contentful Paint (LCP)

How long the biggest visible element takes to render. Google's Core Web Vital for loading speed.

Cumulative Layout Shift (CLS)

How much visible content jumps around as the page loads, scored from the measured CLS value.

Total Blocking Time (TBT)

How long the main thread is blocked by JavaScript during load - the lab-measurable proxy for real-world interaction delay.

Time to First Byte (TTFB)

How long the server takes to respond before any rendering can start - a server/hosting/CDN signal, not a frontend one.

Speed Index

How quickly the page's content is visually populated, frame by frame, not just when it finishes.

Render-blocking resources

CSS and synchronous scripts that delay first paint, flagged individually so you know exactly what to defer or inline.

How it works

Two full passes, one scan.

Desktop pass

A full performance audit under desktop network and CPU conditions.

Mobile pass

The same page, re-audited at a 375px viewport with throttled conditions - mobile and desktop scores often diverge significantly.

Framework-aware fixes

Scanverra detects your stack first, so a Next.js site gets next/image and priority-loading guidance, not generic "optimize your images" advice.

FAQ

Frequently asked questions

Both. Every audit is a controlled, repeatable lab run on Scanverra's own infrastructure, and when there is enough traffic data for your site we add real-visitor field data from the last 28 days alongside it, so you can compare a controlled audit against how real visitors actually experienced your site.

Different network and CPU throttling profiles, plus a narrower 375px viewport that can trigger layout issues invisible on desktop. A site heavy on unoptimized images or third-party scripts typically loses more points on mobile.

It means the metrics we measure are in good shape on the audited page, under the audit's conditions. It doesn't cover every possible performance factor (e.g. server response time under real load, CDN edge coverage) - treat it as a strong signal, not an absolute guarantee.

Yes - run the audit again with a different URL. Each scan is independent, so you can spot-check your homepage, a product page, and a blog post separately rather than assuming one page represents the whole site.

Related audits

Website Audit

Run a free instant audit for performance, SEO, accessibility, and best practices.

SEO Audit

Check crawlability, metadata, structured data, and AI-agent discoverability.

Accessibility Audit

See exactly which WCAG 2.1/2.2 success criteria your site fails, and why.

Security Audit

Turn a header/vulnerability scan into SOC 2 and GDPR control evidence.

Website Speed Audit

How fast your site loads, in plain language - one number, no jargon.

Core Web Vitals Audit

Check LCP, CLS, and INP against Google's thresholds, lab and field.

Broken Link Checker

Crawl a page's links and find the ones that are dead before your users do.

Security Headers Checker

CSP, HSTS, and every other HTTP security header - analyzed, not just listed.

Open Graph Checker

See whether your page has the og:title, og:description, and og:image tags social platforms need.

Schema Markup Checker

Check whether your page ships JSON-LD structured data search engines and AI agents can read.

Sitemap Checker

Check whether your sitemap.xml is reachable, valid, and free of common mistakes.

Redirect Checker

Trace a URL's redirect chain and catch loops, excess hops, and HTTPS-to-HTTP downgrades.

SSL Checker

Test your SSL certificate for expiry, hostname match, chain trust, TLS version, key strength and HSTS in seconds.

Color Contrast Checker

Calculate the WCAG contrast ratio of any two colors and see AA and AAA results, with a suggested accessible color.

Website Technology Checker

Find out which CMS, framework, ecommerce platform and libraries a website is built with.

robots.txt Checker

Check syntax, sitemap lines and size limits, and test whether Googlebot or any crawler can access a URL.

Canonical Checker

Find missing, duplicate, relative or conflicting canonical tags and check that the canonical URL loads.

Hreflang Checker

Validate language codes, x-default and self-references, and confirm every alternate page links back.

Meta Tag Checker

Check title tags, meta descriptions, H1 headings, robots, viewport and Open Graph tags on any page.

HTTP Status Checker

Check up to 20 URLs at once for 200, 301, 404 and 500 responses and redirect chains.

CSP Evaluator

Check a Content-Security-Policy for unsafe-inline, unsafe-eval, wildcards, missing object-src and base-uri, from a URL or pasted policy.

Mixed Content Checker

Find http:// scripts, stylesheets, iframes and images on HTTPS pages that browsers block or warn about.

Alt Text Checker

Find images with missing, empty, file-name or overly long alt text on any page, for accessibility and image SEO.

API Key Leak Checker

Scan a website's public HTML and JavaScript for exposed API keys, tokens and secrets.

MCP Security Scanner

Find unpinned MCP servers, leaked tokens and risky agent settings in your repo.

Vibe Coding Security

Check AI-written code for secrets, injection flaws and risky dependencies.

ADA Compliance Checker

Test your site against the WCAG criteria ADA cases reference.

EAA Compliance Checker

Check your site against the WCAG basis of the European Accessibility Act.

For Agencies

Audit client sites for SEO, speed, accessibility and security on one team plan.

Fix guides

Fix Largest Contentful Paint

Fix Cumulative Layout Shift

Fix slow Time to First Byte

All how-to guides

Run a free performance audit

Desktop and mobile, every Core Web Vital, with framework-aware fixes.

Run free audit