# promises-aplus/promises-spec

An open standard for sound, interoperable JavaScript promises—by implementers, for implementers.

Repository: https://github.com/promises-aplus/promises-spec
Canonical: https://ross.abutalabs.com/products/promises-spec
Homepage: https://promisesaplus.com/
License: CC0-1.0
License Family: permissive
Last push: 2023-08-02T03:40:12+00:00

## Health v2 (maintenance only)
Score: 32/100 (v2, computed 2026-09-02T17:46:02.011165+00:00)
- activity 0, release rhythm 35, longevity 100
- inputs: {"age_days": 5061, "days_push": 1127, "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 1839, forks 159 (observed 2026-08-28T04:05:42.959284+00:00)

## What it is
Promises/A+ is an open specification defining the behavior of the `then` method for interoperable JavaScript promises. It is a stable standard that promise library implementers conform to, not a runnable library itself.

## Use cases
- implement a promise library that interops with others
- understand how JavaScript promises and thenables work
- verify a promise implementation conforms to the standard
- learn promise states and resolution semantics
- reference the then method contract for async code

## When to choose
- you are building or auditing a promise implementation
- you need the authoritative definition of promise/thenable behavior
- you want a stable, widely adopted async interop standard

## When to avoid
- you need a runnable promise library to use in app code (use native promises or a library)
- you need promise creation/combination utilities, which the spec deliberately omits

## Facets
- artifact type: learning-resource
- maturity: stable
- function: concurrency, documentation, developer-tools
- domain: web-development, apis
- platform: browser, cross-platform
- tags: promises, specification, async, then, interop-standard, javascript, specifications, async-programming, nodejs

## Member repositories
- promises-aplus/promises-spec (main) score 32

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:05:42.959284+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 2026-08-30T03:18:15.086207+00:00, confidence not recorded.
  - readme: https://github.com/promises-aplus/promises-spec (fetched 2026-08-28T04:05:42.959284+00:00, sha b89b67f3a5a8)
  - homepage: https://promisesaplus.com/ (fetched 2026-08-29T10:57:46.033247+00:00, sha ecd4a469d6a7)
  - site_page: https://promisesaplus.com/changelog (fetched 2026-08-29T10:57:46.042306+00:00, sha a68dbdcaccee)
- Data as of 2026-08-30T08:39:29.467469+00:00.