# Web Components Polyfills

Web Components Polyfills

Repository: https://github.com/webcomponents/polyfills
Canonical: https://ross.abutalabs.com/products/web-components-polyfills
Language: HTML
License: BSD-3-Clause
License Family: permissive
Last push: 2026-06-22T12:26:38+00:00
Link (homepage): http://webcomponents.org/polyfills/

## Health v2 (maintenance only)
Score: 72/100 (v2, computed 2026-09-02T17:46:02.011165+00:00)
- activity 88, release rhythm 35, longevity 100
- inputs: {"age_days": 2694, "days_push": 72, "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 1189, forks 168 (observed 2026-08-28T04:03:55.724422+00:00)

## What it is
A suite of polyfills that implement the HTML Web Components specs (custom elements, shadow DOM, HTML imports) for browsers lacking native support. It is maintained in the webcomponents/polyfills monorepo after migrating from webcomponents/webcomponentsjs.

## Use cases
- support web components in older browsers
- polyfill custom elements and shadow DOM
- run web components on legacy browsers like IE11
- load web components polyfills in my app
- make custom elements work without native support

## When to choose
- your app must support older browsers without native Web Components support
- you use frameworks or libraries built on Web Components that depend on these polyfills

## When to avoid
- you only target modern browsers with native custom elements and shadow DOM support
- you need a full UI framework rather than spec polyfills

## Facets
- artifact type: library
- maturity: maintenance
- function: ui-components, frontend-framework
- domain: web-development, frontend, browser-extensions
- platform: browser
- tags: web-components, polyfills, custom-elements, shadow-dom, html, javascript

## Member repositories
- webcomponents/polyfills (main) score 72
- webcomponents/webcomponentsjs (mirror) score 10

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:03:55.724422+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 2026-08-29T18:25:56.622205+00:00, confidence not recorded.
  - readme: https://github.com/webcomponents/polyfills (fetched 2026-08-28T04:03:55.724422+00:00, sha 3fe7f864312d)
  - homepage: http://webcomponents.org/polyfills/ (fetched 2026-08-29T09:20:30.349421+00:00, sha 42ea62076c69)
- Data as of 2026-08-30T08:39:29.467469+00:00.