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Running Your First Scan

Once you’ve added a site, you’re ready to run your first scan.

  1. Go to Dashboard → Sites and click on your site.
  2. Click the Start New Scan button on the site detail page.
  3. PerfLeaf queues the scan job and the status changes to In Progress.

The crawler visits your site using a headless browser (Playwright) and for each page it collects:

  • Core Web Vitals — LCP, CLS, INP, FCP, TTFB
  • Asset sizes — JavaScript, CSS, images, HTML
  • Accessibility issues — automated scan for WCAG violations
  • Security headers — HTTPS, CSP, HSTS, X-Frame-Options, etc.
  • DOM metrics — node count, tree depth, tag counts
  • CO₂ emissions — estimated carbon cost of loading the page
  • Tech stack — detected frameworks and libraries
  • Screenshot — visual snapshot of the page

Depending on the size of your site and your plan’s page limit, scans typically complete in a few seconds to a few minutes.

PerfLeaf supports two crawl modes. The mode available to you depends on your plan:

ModeWhat it doesPlan
Single pageCrawls only the homepage (or a specified URL)All plans
Full siteFollows all internal links and/or sitemap entriesGrow / Bloom

See Scan Modes for a full comparison.

While a scan is running you’ll see a live progress bar on the site detail page and on the sites list. You can also cancel a running scan by clicking the Cancel Scan button — the report will be marked as Cancelled.

When the scan completes the report is available immediately. Click View Report to open it, or read Understanding Results for a guided tour.