Performance Analysis

Core Web Vitals performance audits with AI fix suggestions.

Performance analysis runs against your site in a real browser and provides a detailed breakdown of Core Web Vitals, performance metrics, and optimization opportunities. Each failing metric comes with an AI-generated fix prompt.

#Speed

Takes 10-30 seconds depending on your site's complexity. The analysis runs in a headless browser on Vergate's infrastructure.

#Metrics Evaluated

Metric	What It Measures	Good Threshold
LCP	Largest Contentful Paint — main content loads	< 2.5s
FID	First Input Delay — interactivity responsiveness	< 100ms
CLS	Cumulative Layout Shift — visual stability	< 0.1
TBT	Total Blocking Time — main thread blocked	< 200ms
FCP	First Contentful Paint — first visual content	< 1.8s
SI	Speed Index — when content becomes visible	< 3.4s
TTI	Time to Interactive — fully interactive	< 3.8s

#HTTP Performance Checks

In addition to browser-based metrics, Vergate runs 11 browser resource quality checks:

HTML structure — DOCTYPE, charset, viewport meta
Bundle sizes — JS/CSS files over 250KB flagged
Third-party scripts — Too many external scripts slow you down
Caching headers — Static assets should have long cache lifetimes
Preconnect hints — Missing preconnect for critical third-party domains
Font loading — Render-blocking web fonts
Image optimization — Missing lazy loading, oversized images

Tip. HTTP checks give you a quick performance overview in 2-5 seconds, even when the full browser-based analysis isn't available.

#API Usage

Run performance analysis

POST /api/v1/performance
Authorization: Bearer pk_...

{
  "url": "https://example.com",
  "mode": "desktop"
}

#Desktop Mode

Desktop analysis reflects a typical desktop browsing experience with a wider viewport and no throttling.