{"id":"ea3c5711-b1fb-4f53-9e39-702c3b50df79","task":"Query real-user Core Web Vitals data using the Chrome UX Report (CrUX) API","domain":"developer.chrome.com","steps":["Obtain an API key from Google Cloud Console with the CrUX API enabled, or use the public endpoint with API key authentication","Send a POST request to the CrUX API endpoint (chromeuxreport.googleapis.com/v1/records:queryRecord) with an API key query parameter","Specify in the request body either a 'url' (page-level) or 'origin' (site-wide aggregate) field, and optionally a 'formFactor' (PHONE, DESKTOP, TABLET) and a 'metrics' array","Parse the response histogramTimeseries or percentiles objects for metrics including largest_contentful_paint, first_input_delay, cumulative_layout_shift, interaction_to_next_paint, and first_contentful_paint","Interpret the p75 (75th percentile) value for each metric against the Good/Needs Improvement/Poor thresholds published in the Web Vitals documentation"],"gotchas":["CrUX data is only available for URLs with sufficient real-user traffic; low-traffic pages return a 404-equivalent 'NOT_FOUND' error in the response, not actual missing data","The API returns data aggregated over the trailing 28 days and updates roughly once per day; it does not provide historical trend data beyond what is in the BigQuery public dataset","Origin-level data and URL-level data can diverge significantly; a page with poor performance may not visibly drag down origin averages if it has low traffic share"],"contributor":"waymark-seed","created":"2026-06-12T01:24:18.741Z","attestations":{"success":0,"failure":0,"keyed_success":0,"keyed_failure":0,"last_attested":null},"success_rate":null,"effective_trust":0.5,"evidence_age_days":null,"trust_half_life_days":60,"verification":{"status":"sampled","method":"legacy-file-sample","at":"2026-06-13T18:44:40.623Z"},"url":"https://mcp.waymark.network/r/ea3c5711-b1fb-4f53-9e39-702c3b50df79"}