# GoogleChrome/web-vitals

Essential metrics for a healthy site.

Repository: https://github.com/GoogleChrome/web-vitals
Canonical: https://ross.abutalabs.com/products/web-vitals
Homepage: https://web.dev/vitals
Language: JavaScript
License: Apache-2.0
License Family: permissive
Last push: 2026-08-26T19:06:24+00:00

## Health v2 (maintenance only)
Score: 77/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 99, release rhythm 35, longevity 100
- inputs: {"age_days": 2354, "days_push": 7, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_releases
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 8593, forks 521 (observed 2026-08-28T04:10:23.703733+00:00)

## What it is
A tiny (~3KB) JavaScript library from Google for measuring Web Vitals metrics (CLS, INP, LCP, FCP, TTFB) on real users in the browser, matching how Chrome measures them. It reports metrics via callbacks so results can be sent to analytics endpoints.

## Use cases
- measure core web vitals on real users
- track CLS LCP INP in production
- send page performance metrics to analytics
- monitor real user performance of my website
- collect RUM performance data in the browser
- report web vitals to google analytics

## When to choose
- you need field (real-user) Web Vitals measurements matching Chrome's methodology
- you want a tiny, dependency-free metrics library for any website
- you want to pipe Core Web Vitals into your own analytics or RUM backend

## When to avoid
- you need lab/synthetic load testing rather than real-user measurement
- you need a full RUM platform with dashboards rather than a measurement library
- you need server-side or non-browser performance monitoring

## Facets
- artifact type: library
- maturity: active
- function: analytics, monitoring, developer-tools
- domain: web-development, frontend, performance, analytics
- platform: browser
- tags: web-vitals, core-web-vitals, rum, performance-metrics, cls, lcp, inp, real-user-monitoring, nodejs

## Member repositories
- GoogleChrome/web-vitals (main) score 77

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:10:23.703733+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-29T17:26:12.595949+00:00, confidence not recorded.
  - readme: https://github.com/GoogleChrome/web-vitals (fetched 2026-08-28T04:10:23.703733+00:00, sha 8a493b3d7fcc)
  - homepage: https://web.dev/vitals (fetched 2026-08-29T08:26:49.334819+00:00, sha adfac481a596)
  - site_page: https://web.dev/about (fetched 2026-08-29T08:26:49.344224+00:00, sha d223d27e33e8)
  - site_page: https://web.dev/articles/vitals-measurement-getting-started (fetched 2026-08-29T08:26:49.346125+00:00, sha c127e87c3ef8)
  - site_page: https://web.dev/articles/lab-and-field-data-differences (fetched 2026-08-29T08:26:49.348094+00:00, sha e036866da089)
- Data as of 2026-08-30T08:39:29.467469+00:00.