Core Web Vitals History tools show how a site's LCP, INP and CLS have changed over time using Google's CrUX data. See how they work and where to find them.
Core Web Vitals History tools are free, web-based utilities that chart how a website's Core Web Vitals metrics, Largest Contentful Paint, Interaction to Next Paint, and Cumulative Layout Shift, have trended over recent months. Instead of a single point-in-time score, they pull from Google's Chrome UX Report (CrUX) History API, which stores rolling real-user measurement data collected from actual Chrome browser visits.
Because this is the same field data that underlies Google PageSpeed Insights and the Core Web Vitals report in Google Search Console, these history tools essentially save site owners from manually checking those reports over and over to spot trends. Several tools use this exact naming or purpose, including checkers from Rumvision and punits.dev, a charting feature inside the open-source Unlighthouse project, and a Chrome Web Store browser extension.
These tools query Google's public CrUX History API, which typically returns roughly six months of monthly or weekly snapshots for a given origin or URL, broken out by device type (phone versus desktop) and, in more detailed implementations, connection type.
Because CrUX only publishes data for pages that receive enough Chrome traffic to meet Google's aggregation and privacy thresholds, lower-traffic pages, and sometimes even entire smaller sites, may show as having insufficient historical data, particularly at the individual-URL level rather than the whole-domain (origin) level.
Lab-based tools such as Lighthouse or a single PageSpeed Insights run measure one simulated page load under controlled conditions, which is useful for debugging but does not represent the range of real devices and networks actual visitors use.
Core Web Vitals History tools are better suited to answering a different question: did a specific optimization, deployment, or redesign measurably improve (or regress) real-user experience over the following weeks or months. Many teams use both together, lab tools for diagnosis and history tools for verification.
It charts a website's historical Largest Contentful Paint, Interaction to Next Paint, and Cumulative Layout Shift scores using Google's CrUX (Chrome UX Report) field data, typically covering the trailing six months.
It draws from the same underlying CrUX dataset that powers PageSpeed Insights and Google Search Console's Core Web Vitals report, but presents it as a historical trend chart rather than a single current score.
Yes, the tools in this category, including implementations from Rumvision, punits.dev, TameTheBots, Unlighthouse, and a Chrome Web Store extension, are free to use.
Google's CrUX dataset only reports data for origins and pages that receive enough real Chrome traffic to meet its privacy and aggregation thresholds; lower-traffic sites or individual pages often will not have published data.
Most implementations show roughly six months of history, since that is the typical window available through the CrUX History API, though some tools extend coverage further.
Yes, CrUX reports phone and desktop data separately, and most history tools let users toggle between the two device categories.
They serve different purposes: Lighthouse gives a detailed lab diagnosis of a single page load, while history tools show whether real visitors actually experienced better performance over time, so they work best used together.
Some tools support URL-level checks in addition to origin-level (whole-domain) checks, though URL-level data is less consistently available due to CrUX's traffic thresholds.