Skip to main content
1-second delay = 7% conversion drop

Every second slower costs you revenue

Aperion's Performance agent benchmarks every page against Core Web Vitals and Lighthouse scores - identifying render-blocking resources, oversized images, and slow server responses - then tells you exactly what to fix.

Start your performance audit See how it works

Checks LCP · CLS · INP · FCP · TTFB · Lighthouse scores · Resource audit

The risk is real

Slow pages cost you rankings, sales, and trust

Conversion loss

1 second delay = 7% fewer conversions

Amazon calculated a 1% revenue loss per 100ms delay. For a site doing £1M/year, a 2-second slowdown costs £140,000. Speed is a business metric.

SEO ranking drop

Page speed is a direct Google ranking signal

Google's Core Web Vitals are a confirmed ranking factor since 2021. Poor LCP, CLS, or INP actively penalises your search position against faster competitors.

Bounce rate spike

53% of mobile visits abandoned if > 3s load

More than half of mobile visitors leave before a slow page loads. That is paid traffic, organic traffic, and word-of-mouth referrals - gone.

User frustration

Performance is perceived quality

Slow websites signal low quality, low trust, and low investment. Performance directly shapes brand perception - especially on first visit.

Setup

Performance monitoring in 3 steps

No code changes. No browser extensions. Real Lighthouse data for every page.

Add your URL

Aperion captures real Lighthouse data and performance metrics for every page, simulating real user conditions. No code changes or browser extensions required.

AI diagnoses bottlenecks

Every performance metric analysed: render-blocking resources, image optimisation, server response time, caching policies, and third-party script impact.

Get prioritised fixes

Each issue ranked by performance impact. Know which optimisations deliver the biggest score improvements with the least effort.

Performance Coverage

Every metric. Every page.

Aperion measures all Core Web Vitals, Lighthouse category scores, and resource-level diagnostics - giving you a complete picture of performance health across every page, not just a site-wide average.

7

CWV metrics

4

Lighthouse scores

Res.

Resource diagnostics

Start your performance audit
  • LCP - Largest Contentful Paint (Good: < 2.5s, Poor: > 4s)
  • CLS - Cumulative Layout Shift (Good: < 0.1, Poor: > 0.25)
  • INP - Interaction to Next Paint (Good: < 200ms, Poor: > 500ms)
  • FCP - First Contentful Paint (Good: < 1.8s)
  • TTFB - Time to First Byte (Good: < 800ms)
  • Performance score (0-100)
  • Accessibility score (0-100)
  • Best Practices score (0-100)
  • SEO score (0-100)
  • Tested across mobile and desktop device profiles
  • Image optimisation - format, compression, sizing
  • Render-blocking JavaScript and CSS
  • Unused JavaScript (kilobytes saved)
  • Font loading strategy and display swap
  • Third-party script impact on load time
  • Cache-Control and Expires header coverage
  • TTFB - server response time
  • Compression - gzip and Brotli support
  • HTTP/2 and HTTP/3 protocol usage
  • CDN usage and edge caching
  • Redirect count and redirect chains
  • DNS lookup time

Audit output

See exactly what an Aperion performance report looks like

Structured, machine-readable reports with every metric result, resource diagnosis, and prioritised fix instructions.

Poor performance detected

Performance overview

Lighthouse performance score is 54 - in the "needs improvement" range. LCP, CLS, and FCP are all failing. This site is being actively penalised in search rankings and losing conversions on every page load.

54

Lighthouse score

Poor

Performance grade

{
  "lighthouse_score": 54,
  "lcp": "3.8s",
  "cls": 0.14,
  "inp": "220ms",
  "fcp": "2.9s",
  "ttfb": "1.2s",
  "performance_grade": "poor"
}
Core Web Vitals not passing

Core Web Vitals breakdown

LCP and CLS are both poor, directly hurting rankings. INP needs improvement. Only fixing LCP will have the largest single impact on both performance score and search visibility.

Estimated ranking impact

Fixing LCP alone could move 3+ ranking positions on competitive queries

{
  "lcp_status": "poor",
  "cls_status": "poor",
  "inp_status": "needs-improvement",
  "fcp_status": "needs-improvement",
  "all_vitals_pass": false
}

Lighthouse category scores

Performance at 54 needs significant improvement. Accessibility and Best Practices are in the moderate range. SEO score is strong at 91, suggesting the core on-page elements are in order.

Performance

54

Accessibility

78

Best Practices

83

SEO

91

{
  "performance": 54,
  "accessibility": 78,
  "best_practices": 83,
  "seo": 91,
  "tested_device": "mobile"
}

Resource diagnostics

Six render-blocking resources are delaying the start of page rendering. 284KB of unused JavaScript is being loaded on every page. Twelve unoptimised images are adding 4.8MB of unnecessary weight.

  • 6 render-blocking resources
  • 284 KB unused JavaScript
  • 12 unoptimised images
  • 4.8 MB total page weight 
{
  "render_blocking_resources": 6,
  "unused_javascript_kb": 284,
  "unoptimised_images": 12,
  "total_page_weight_kb": 4821
}
Top fix: render-blocking JS

Prioritised fix plan

Eliminating render-blocking JavaScript is the highest-impact fix - estimated to improve LCP by 1.4 seconds and boost the Lighthouse score by 18 points. Medium effort with a large return.

  • Estimated LCP gain: 1.4 seconds
  • Estimated score gain: +18 points
  • Effort: medium
  • Highest priority of 6 issues 
{
  "top_fix": "render-blocking JS",
  "estimated_lcp_gain": "1.4s",
  "estimated_score_gain": 18,
  "effort": "medium"
}

Frequently asked questions

Aperion tracks all five Core Web Vitals (LCP, CLS, INP, FCP, TTFB), four Lighthouse category scores (Performance, Accessibility, Best Practices, SEO), and resource-level diagnostics including render-blocking resources, unused JavaScript, unoptimised images, page weight, caching headers, compression, and third-party script impact. Every metric is measured per page so you get granular diagnostics, not just a site-wide average.
The relationship between speed and conversions is direct and measurable. Amazon found a 1% revenue loss per 100ms of added latency. Google data shows that pages loading in 1-3 seconds have a 32% higher bounce rate than pages loading in under 1 second. For mobile, 53% of visitors abandon a page that takes more than 3 seconds to load. Every additional second of load time is a conversion loss multiplier.
Core Web Vitals are a set of performance metrics defined by Google to measure real user experience. LCP (Largest Contentful Paint) measures loading performance - good is under 2.5 seconds. CLS (Cumulative Layout Shift) measures visual stability - good is under 0.1. INP (Interaction to Next Paint) measures responsiveness - good is under 200ms. FCP (First Contentful Paint) and TTFB (Time to First Byte) measure initial loading speed. All are confirmed Google ranking factors.
Lighthouse scores from 0-100 are colour-coded: 0-49 is poor (red), 50-89 needs improvement (amber), and 90-100 is good (green). For the Performance category specifically, a score above 90 is the target. Most production websites score between 50-75. Scores below 50 indicate significant performance problems that are likely affecting both rankings and user experience. Aperion tracks Lighthouse scores for Performance, Accessibility, Best Practices, and SEO.
Performance regressions are introduced with every deployment - a new JavaScript bundle, a larger hero image, or a new third-party script can all degrade Core Web Vitals. Aperion supports scheduled monitoring so you are notified immediately when a regression is detected. For most sites, weekly monitoring is a minimum. For e-commerce or high-traffic sites, daily monitoring ensures regressions are caught before they compound into significant revenue loss.
Yes. Aperion's Performance agent goes beyond reporting a score - it identifies the specific resources causing slowness. This includes render-blocking JavaScript and CSS files, oversized or unoptimised images (with estimated savings), unused JavaScript bundles (in kilobytes), slow server response times, missing compression, inefficient caching policies, and third-party script impact. Each issue is ranked by its estimated performance gain, so you know exactly where to focus effort.

Start optimising your site's performance

Join the waitlist for early access. Catch performance regressions before they cost you rankings and revenue.

No credit card required. Start with 3 pages free.