# Project Fluent

Fluent — planning, spec and documentation

Repository: https://github.com/projectfluent/fluent
Canonical: https://ross.abutalabs.com/products/project-fluent
Homepage: https://projectfluent.org
Language: JavaScript
License: Apache-2.0
License Family: permissive
Topics: intl, localization, l10n, internationalization, globalization, translate, translation, ftl, specification, asdl, ebnf
Last push: 2026-03-21T10:28:57+00:00
Link (homepage): https://projectfluent.org

## Health v2 (maintenance only)
Score: 56/100 (v2, computed 2026-09-02T17:46:02.011165+00:00)
- activity 73, release rhythm 8, longevity 100
- inputs: {"age_days": 3529, "days_push": 165, "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 1674, forks 47 (observed 2026-08-28T04:05:20.444874+00:00)

## What it is
Fluent is a localization system whose FTL syntax lets translators write natural-sounding, asymmetric translations with locale-specific logic like plurals, genders, and grammatical cases. This repository hosts the specification, EBNF grammar, reference parser implementation, and documentation for the ecosystem of JS, Python, and Rust implementations.

## Use cases
- localize my app into multiple languages with proper plural rules
- write translations that adapt to grammatical gender and cases
- parse FTL translation files into an AST
- define a translation file format for translators
- integrate localization into React apps
- validate Fluent syntax against a formal grammar

## When to choose
- you need expressive, locale-independent translations beyond simple key-value strings
- you want a well-specified, multi-language localization format with mature implementations
- you're building localization tooling and need the reference parser or spec

## When to avoid
- you only need simple key-value string replacement with no grammar logic
- you need a production runtime — use fluent.js, fluent-rs, or python-fluent instead of this reference repo
- you need machine translation or translation management workflow features

## Facets
- artifact type: library
- maturity: stable
- function: internationalization, parser, templating, documentation
- domain: web-development, developer-tools, apis
- platform: cross-platform, python, rust
- tags: l10n, ftl, translation-resources, specification, reference-implementation, ebnf-grammar, localization, nodejs, web-server

## Member repositories
- projectfluent/fluent (main) score 56
- projectfluent/fluent-rs (sdk) score 67
- projectfluent/fluent.js (sdk) score 71

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:05:20.444874+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 2026-08-30T03:42:30.181378+00:00, confidence not recorded.
  - readme: https://github.com/projectfluent/fluent (fetched 2026-08-28T04:05:20.444874+00:00, sha 7185421b663e)
  - homepage: https://projectfluent.org (fetched 2026-08-29T11:15:54.046457+00:00, sha 78c8460c0736)
- Data as of 2026-08-30T08:39:29.467469+00:00.