# webcomponents/custom-elements-everywhere

Custom Element + Framework Interoperability Tests.

Repository: https://github.com/webcomponents/custom-elements-everywhere
Canonical: https://ross.abutalabs.com/products/custom-elements-everywhere
Homepage: https://custom-elements-everywhere.com
Language: JavaScript
License: NOASSERTION
License Family: other
Last push: 2026-08-17T23:01:13+00:00

## Health v2 (maintenance only)
Score: 76/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 98, release rhythm 35, longevity 100
- inputs: {"age_days": 3303, "days_push": 16, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_releases, no_license
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1256, forks 108 (observed 2026-08-28T04:04:09.268346+00:00)

## What it is
A project that runs Karma test suites against major JavaScript frameworks to evaluate how well they interoperate with Custom Elements (Web Components). Results are published as a comparison website with per-framework scores and notes on data and event handling.

## Use cases
- compare how frameworks handle custom elements
- check if react works with web components
- find framework interoperability issues with custom elements
- see which frameworks pass custom element tests
- decide which framework to use with web components
- learn how frameworks pass properties vs attributes to custom elements

## When to choose
- evaluating framework compatibility with Web Components before adoption
- contributing to or tracking framework interop discussions
- looking for documented workarounds for custom element data/event handling

## When to avoid
- you need a testing library for your own app rather than a comparison resource
- you need production tooling rather than reference test suites

## Facets
- artifact type: learning-resource
- maturity: active
- function: testing, e2e-testing, benchmarking, developer-tools
- domain: web-development, frontend, developer-tools, testing
- platform: browser
- tags: web-components, custom-elements, framework-interop, karma-tests, compatibility-tests, nodejs, web-server

## Member repositories
- webcomponents/custom-elements-everywhere (main) score 76

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:04:09.268346+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 2026-08-30T05:07:17.950856+00:00, confidence not recorded.
  - readme: https://github.com/webcomponents/custom-elements-everywhere (fetched 2026-08-28T04:04:09.268346+00:00, sha 3c638a09927e)
  - homepage: https://custom-elements-everywhere.com (fetched 2026-08-29T12:17:41.768799+00:00, sha 5e660f4ffd05)
- Data as of 2026-08-30T08:39:29.467469+00:00.