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URLpipe

Web endpoint

Check a page's Core Web Vitals

Paste a link and get Largest Contentful Paint, Cumulative Layout Shift and Total Blocking Time from a real Lighthouse run — each marked good, needs improvement or poor.

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  • Powered by the URLpipe API

Try it on a page

Try your own URL

Free · no signup · 2 runs every 10 minutes

Paste up to 10 URLs

Each URL counts as one of your free runs; the ones past the limit are listed with a free API key to run them.

Your result will appear here.

Pick one of the pages above to get started.

What you get

  • LCP, CLS and TBT, each against Google's good and poor thresholds
  • One pass-or-fail verdict for the page
  • First Contentful Paint and the Lighthouse performance score
  • The metrics as JSON you can copy

How it works

  1. 1We run Google Lighthouse 13 against the live page, on its default mobile profile.
  2. 2Each metric is compared with Google's published thresholds: LCP is good at 2.5 s or less, CLS at 0.1 or less, and Total Blocking Time at 200 ms or less.
  3. 3You get a verdict per metric and for the page, with the numbers underneath.

What people use it for

  • Check whether a page is likely to pass Core Web Vitals before a release
  • Find which of the three is holding a page back
  • Track LCP and CLS on key pages from CI, through the API

Frequently asked

Is this the same as the Core Web Vitals report in Search Console?
No. Search Console reports field data — what real Chrome users experienced over the last 28 days. This is a lab test: one load on a throttled mobile profile. It is repeatable and works on any URL, including pages with no traffic yet, but it can differ from what your visitors see. Use it to find problems, and field data to confirm them.
Why Total Blocking Time instead of INP?
Interaction to Next Paint needs a person clicking and typing, so no lab test can measure it. Total Blocking Time — how long the main thread was too busy to respond during load — is the lab metric that tracks it most closely, and the one Lighthouse weighs most: 30% of the performance score.
Why do my numbers change between runs?
Lab timings move with network and CPU conditions at the moment of the run. The demo keeps each result for 7 days, so checking the same URL again shows the same audit; through the API, max_age decides how fresh an audit has to be.
Can I run this in CI?
Yes. POST /lighthouse with a free API key returns the same metrics as JSON, at 2 credits an audit.

Related

/lighthouse API docsCore Web Vitals: lab vs fieldTake a full-page screenshot of any websiteScreenshot a website the way a phone shows itScreenshot a website in dark modeAll free tools

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