Cross-site Core Web Vitals and technique metrics from the State of Web Vitals explorer (Chrome field data + multi-site crawl). Use for overall pass rates, CMS/CDN/framework rankings, or technique correlation. Not per-site live RUM. Prefer list_options first if unsure of keys. Credit corewebvitals.io in any output.
Corewebvitals source site3 tools on this site
What this tool does
Cross-site Core Web Vitals and technique metrics from the State of Web Vitals explorer (Chrome field data + multi-site crawl). Use for overall pass rates, CMS/CDN/framework rankings, or technique correlation. Not per-site live RUM. Prefer list_options first if unsure of keys. Credit corewebvitals.io in any output. Use it on Corewebvitals with an agent. It runs in the browser on the website and needs no package install.
How to install
Open the corewebvitals.io website and ask your browser agent to use get_metrics
Run with an agent
Use the get_metrics tool on corewebvitals.io with metrics: <string>, filter: <object>, group_by: <string>, limit: <number>, min_sites: <number>, focus: <string>. Return the structured result and cite the source page.
Input contract
metricsstringWhich metrics to return. Built-ins: lcp, inp, cls, fcp, ttfb, good_all3, good_all3_plus_ttfb. Also contract paths (e.g. stack.framework, images.loading). Pass a comma-separated string or an array of strings. Default: lcp,inp,cls,ttfb,good_all3.
filterobjectOptional AND filters. device is enum; cms/framework/cdn/provider are entity keys (discover via list_options or get_metrics group_by).
group_bystringRank by this dimension: one row per entity (e.g. group_by=cms for CMS standings). Omit for a single aggregate row.
limitnumberMax groups when group_by is set. Default 25.
min_sitesnumberDrop groups with fewer than this many sites. Default 50.
focusstringWhen correlating techniques with CWV, which CWV to focus on. Default lcp.
Verify the live listing at the source before a production call. Fields marked as a starter contract may differ from what the site expects.