CLS Scanner - Sitemap & Layout Shift Tool
Audit image-related CLS issues, nested sitemap URLs, and export client-ready reports with PageSpeed Insights context.
What CLS Scanner helps you do
CLS Scanner helps SEOs, developers, and agencies find image-related layout-shift risks faster while keeping the workflow practical for both single-page checks and bulk audit reviews.
Image-Focused CLS Audits
Check image dimensions, rendered sizing mismatches, and accessibility details that contribute to unstable layouts.
Agency-Friendly Reporting
Save audit history, compare runs, and export reports that are easier to share with clients or internal stakeholders.
How to Install
- 1Open the Chrome Web Store listing from this page.
- 2Click Add to Chrome and approve the install prompt.
- 3Pin CLS Scanner from the Chrome toolbar if you want faster access while auditing.
Install CLS Scanner directly from the Chrome Web Store for the fastest setup.
How to Use It
- 1Open the page you want to audit, then launch CLS Scanner from the Chrome toolbar or side panel.
- 2Run a single-page scan to review image dimensions, rendered sizing, and CLS-related warnings.
- 3Load a sitemap when you want to audit multiple URLs and compare results in bulk.
- 4Export findings as CSV, JSON, HTML, or a print-friendly report for clients or internal review.
Page Scanning
- Scan the active page from the popup or side panel
- Inspect image URLs, metadata, and rendered sizing
- Review HTML snippets tied to image-related CLS risks
Bulk Sitemap Audits
- Load nested sitemap trees
- Choose exactly which URLs to audit
- Review bulk results in a dedicated dashboard flow
Detailed Audit Insights
- Flag missing HTML width and height attributes
- Surface PSI CLS warnings alongside actual page risk
- Review alt quality, file format, file size, and sizing fit
Exports
- CSV for spreadsheet reviews
- JSON for automation and integrations
- HTML for shareable reports
- Print-friendly flow for PDF export
Who It Is For
- Technical SEO teams
- Web performance specialists
- Developers fixing Core Web Vitals issues
- Agencies preparing client-facing audit reports
Export Formats
CSV
JSON
HTML
PDF-Friendly
Privacy & Data Use
- Core scanning runs locally in the browser.
- Settings, history, and saved audit data stay in Chrome storage.
- Optional PSI reporting sends audited page URLs to Google PageSpeed Insights.
- Pro activation sends license data to Lemon Squeezy.
- Optional analytics can be enabled by the publisher through a proxy without audited page URLs or license keys.
Support & Next Steps
Need bug triage, rollout help, or productization support for CLS Scanner? Use the support page for troubleshooting and license help, or reach out directly if you want a custom browser-based audit workflow for your team.
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