Bulk Website Speed Test — Compare Mobile & Desktop

What the comparison and CSV actually contain

Each URL has separate Mobile and Desktop columns for Performance Score, LCP (ms), FCP (ms), CLS (score), TBT (ms, lab), TTFB (ms, lab; if available), Primary Root Cause and First Action, plus the report disclaimer. Missing measurements are empty, never zero. Field INP is not a lab CSV measurement.

Example: compare page templates

Submit your homepage, one product page and one article. Compare mobile LCP across templates and inspect whether the first action concerns an image, CSS or main-thread work. If desktop looks acceptable but mobile TBT is high, investigate the returned JavaScript evidence rather than assuming hosting is the cause.

Example: prepare a client repair list

Test selected public client URLs and sort device-specific measurements in a spreadsheet. Use First Action to assign investigation, not to promise a score gain. For a before/after check, open the URL in the single-page scanner, retain the report and use Rescan & Compare after a change.

Time, scope and limits

A fresh URL typically takes about 45 seconds. URLs run one after another with a short delay, so a five-URL batch takes several minutes; cached results can be quicker and complex pages can take longer or fail. Bulk request allowance: 10 per minute per IP; AI requests have separate limits. Shared request quotas and concurrent-request limits also apply across the service, independently of IP headers. Fresh scans do not bypass these limits. When capacity or protection is unavailable, new requests pause; existing reports remain readable.

Only submitted URLs are tested. No sitemap is read and no additional pages or broken links are crawled. For page-level metadata findings use the Lighthouse SEO scanner; for lab versus CrUX measurements see the Core Web Vitals checker guide.