# fable-compiler/Fable

F# to JavaScript, TypeScript, Python, Rust, Erlang and Dart Compiler

Repository: https://github.com/fable-compiler/Fable
Canonical: https://ross.abutalabs.com/products/fable
Homepage: http://fable.io/
Language: F#
License: MIT
License Family: permissive
Topics: fsharp, javascript, typescript, dart, python, rust, beam, erlang
Last push: 2026-08-26T19:26:08+00:00

## Health v2 (maintenance only)
Score: 99/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 99, release rhythm 99, longevity 100
- inputs: {"age_days": 3887, "days_push": 7, "days_rel": 8, "gap_med": 8, "n_releases_24m": 26}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 3144, forks 327 (observed 2026-08-28T04:07:45.946190+00:00)

## What it is
Fable is an open-source F# compiler that translates F# code to JavaScript, TypeScript, Python, Rust, Dart, and Erlang/BEAM. It makes F# a first-class citizen of these ecosystems with readable output and rich interop with native packages.

## Use cases
- compile F# to JavaScript for web apps
- write frontend code in F# and use npm packages
- transpile F# to TypeScript
- target Python or Rust from F# code
- build Erlang/BEAM applications in F#
- use F# pattern matching and type inference in JS ecosystem

## When to choose
- you want to write browser or Node.js apps in F#
- you want strong typing and immutability with JavaScript interop
- you want one F# codebase targeting multiple language backends

## When to avoid
- you need full .NET BCL compatibility or reflection-heavy code
- you only target experimental backends like Rust, Dart, or Erlang in production
- your team has no F# experience

## Facets
- artifact type: cli-tool
- maturity: active
- function: compiler, programming-language, developer-tools
- domain: programming-languages, compilers, web-development, frontend, backend
- platform: cross-platform, python, rust, cli
- tags: fsharp, javascript, typescript, dart, erlang, transpiler, functional-programming, npm-interop, compiler, nodejs, web-server

## Member repositories
- fable-compiler/Fable (main) score 99

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:07:45.946190+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 2026-08-30T08:31:32.690800+00:00, confidence not recorded.
  - readme: https://github.com/fable-compiler/Fable (fetched 2026-08-28T04:07:45.946190+00:00, sha a78d69901f41)
  - homepage: http://fable.io/ (fetched 2026-08-29T09:40:40.483164+00:00, sha 12611064305a)
  - site_page: https://fable.io/docs (fetched 2026-08-29T09:40:40.492651+00:00, sha e178504708a1)
  - site_page: https://fable.io/docs/2-steps/setup.html (fetched 2026-08-29T09:40:40.494594+00:00, sha b5b97f04a146)
  - site_page: https://fable.io/docs/javascript/features.html (fetched 2026-08-29T09:40:40.496625+00:00, sha dd6eacd12f40)
  - site_page: https://fable.io/docs/javascript/compatibility.html (fetched 2026-08-29T09:40:40.501347+00:00, sha ff24c7ae0805)
- Data as of 2026-08-30T08:39:29.467469+00:00.