# open-feature/spec

OpenFeature specification

Repository: https://github.com/open-feature/spec
Canonical: https://ross.abutalabs.com/products/open-feature-spec
Homepage: https://openfeature.dev
Language: Python
License: Apache-2.0
License Family: permissive
Topics: specification, feature-flags, openfeature
Last push: 2026-08-25T23:08:02+00:00

## Health v2 (maintenance only)
Score: 67/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 99, release rhythm 8, longevity 100
- inputs: {"age_days": 1664, "days_push": 8, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1245, forks 57 (observed 2026-08-28T04:04:07.069935+00:00)

## What it is
The OpenFeature specification defines a vendor-agnostic, community-driven API standard for feature flag evaluation, maintained as a CNCF incubating project. This repository contains the normative requirements (RFC 2119 style) that SDKs and providers across languages must conform to.

## Use cases
- standardize feature flag evaluation across vendors
- avoid vendor lock-in when switching feature flag tools
- build a conformant OpenFeature SDK for a new language
- implement a custom feature flag provider
- understand requirements for feature flag evaluation context and hooks
- unify multiple flag management systems behind one API

## When to choose
- you want a common, vendor-neutral API for feature flagging across your stack
- you are building or certifying an OpenFeature SDK or provider
- you need to switch or consolidate feature flag platforms without refactoring code

## When to avoid
- you need a runnable feature flag service or UI rather than a specification
- you want a single-vendor feature flag solution with batteries included
- you need flag storage, admin dashboards, or audit trails - the spec only defines the client evaluation API

## Facets
- artifact type: learning-resource
- maturity: active
- function: feature-flags, developer-tools, sdk
- domain: developer-tools, web-development, apis
- platform: cross-platform, python, go, jvm, dotnet
- tags: specification, feature-flags, openfeature, vendor-agnostic, cncf, flag-evaluation, api-standard, automation, nodejs

## Member repositories
- open-feature/spec (main) score 67

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:04:07.069935+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 2026-08-30T05:08:11.081369+00:00, confidence not recorded.
  - readme: https://github.com/open-feature/spec (fetched 2026-08-28T04:04:07.069935+00:00, sha 191b1ddf3698)
  - homepage: https://openfeature.dev (fetched 2026-08-29T12:20:03.659388+00:00, sha 9cff0c72501a)
  - site_page: https://openfeature.dev/docs/tutorials/five-minutes-to-feature-flags (fetched 2026-08-29T12:20:03.668378+00:00, sha d4a21a888b81)
  - site_page: https://openfeature.dev/docs/reference/sdks/server/java (fetched 2026-08-29T12:20:03.670392+00:00, sha 2cf8bc63f25d)
  - site_page: https://openfeature.dev/docs/reference/intro (fetched 2026-08-29T12:20:03.666462+00:00, sha 1005becbb9ad)
  - site_page: https://openfeature.dev/docs/reference/sdks/server/javascript (fetched 2026-08-29T12:20:03.672859+00:00, sha 2e2c2e42f991)
  - site_page: https://openfeature.dev/docs/reference/sdks/server/javascript/nestjs (fetched 2026-08-29T12:20:03.675149+00:00, sha 67f4eafe77e9)
  - site_page: https://openfeature.dev/docs/reference/sdks/server/dotnet (fetched 2026-08-29T12:20:03.676992+00:00, sha 38ca55aa1fc9)
  - site_page: https://openfeature.dev/docs/reference/sdks/server/go (fetched 2026-08-29T12:20:03.679084+00:00, sha 0d2d160ad505)
  - site_page: https://openfeature.dev/docs/reference/sdks/server/python (fetched 2026-08-29T12:20:03.681036+00:00, sha c5c737e087a7)
- Data as of 2026-08-30T08:39:29.467469+00:00.